Interestingly, I can only find one mention in RRoP about looking at your opponents' cards, and it refers specifically to your guests, not to the players themselves:
Nonetheless, as a floor I would consider it cheating if you contorted yourself into a non-natural position and took active measures to view your opponent's cards, and I would treat it as such and bar you from the room for at least some length of time. Basically, if you are behaving in a non-normal way to see cards which your opponent is protecting in a normal way, you are cheating and I will sanction you.

On the flip side, if your opponent is not protecting his hand and you are able to see them, then while you are still gaining an advantage, I would say that you are mainly violating an ettiquette, but it is the other player who I would sanction, absent some disability or other ADA type accommodation which would need to be made. If he refused to protect his hand, then I would remove him. If he requested accommodation but you refused to play nice, however, I would probably still remove you, or at least move you to another table where you would not gain an advantage.

IMO, anyway.

I should also mention this rule:
It is self-referential to say that looking at another players cards is cheating because of the above rule, of course. But I think it implies that there are other things which are self-evidently cheating, and doing them will be sanctioned. This is one of those things to me, but I would agree it is closer to being a question than other things might be (like pulling cards out of your sleeves, or deliberately fouling other players hands, etc.).

I think we all learn about not looking at an opponent's holdings when we first learn 'Go Fish' ... if we need to specifically state that this is deemed unacceptable then we've really taken things a bit far.

The discussion I find much more fascinating is what obligations are Players under to reveal 'extra' information and at what time should they reveal it. And then to what extent does the Floor go to (if any) to verify the correctness of the information.

There are other threads that touch on this but we can derail this thread if we want. GL

For those saying ‘to bad so sad’ and that flasher is responsible for protecting his cards, that may be true between you and him. But don’t forget all the other players at the table. You are gaining information they don’t have access to. You might not consider it cheating him. But I suspect at least some of the other 5 to 8 people consider you to be cheating.

Working to get a glimpse before or after you fold is cheating.
Just seeing but still in hand and not trying to stop it and not sharing you know is at least mildly unethical.

Randomly and innocently seeing AFTER you already folded pretty MEH but probably nice to still warn him as next time you might still be in.

nobody has ever seen my cards before ive wanted them to be seen

As someone with a bad back who can't sit at the table for more than an hour without taking a walk for a few minutes, I completely understand the need to stretch and contort at the table sometimes. So I definitely won't be one to give you a hard time for that. If you're purposely doing it to try to see someone's cards then that's pretty scummy, but it doesn't sound like that's what you're doing.

If someone is exposing their cards or making their cards visible to me because of how they squeeze them, I'll always let them know once. After that, it's on them if they continue to do the same thing. I'd never actively try to look at a player's cards, but I'm also not changing how I sit or physically move at the table because someone cant protect their hand properly. I'll tell you once, and with players that I know are very inexperienced I'll sometimes even suggest a way to protect their cards when looking at them, but after that it's on them. It's very easy to view your cards from any seat at the table without exposing them to other players, so if you can't figure that simple task out after I've already brought it to your attention then I don't know what else to tell you.

I think that there is an ethical standard here that is generally accepted. You simply warn your table partner that they are flashing their cards and that they should be more careful. If after that fair and friendly warning they continue to show their cards to you accidentaly, then I do not believe you have a further obligation.

Now, if they flash their card while mucking or otherwise in a hand that you are in, you still have the ethical obligation to announce that you saw the card and that it should be exposed.

You are more than free to stretch and contort in between hands and whenever your neighbors are not actively looking at their cards.

If your back is so bad that you can't wait 30 seconds for preflop action to finish, you should declare your disability to the table up front so that everyone knows that you will be doing something super annoying out of medical necessity and not doing something super annoying because you're unaware it's super annoying.

First of all, I never said anything about doing it while people were looking at their cards. I'm also not talking about laying over the table or impeding on anyone's personal space at the table.

Secondly, there's no way in hell that I or anyone else should feel required to sit a certain way because someone cant protect their cards. That statement is beyond delusional. Your comment is so off base and makes so many assumptions that it's not even funny. All I said was to OP that I understand the need to stretch at the table. I never said anything about when/how I do so.

Did you read the OP carefully?

This thread exists because he can't sit still for the 2 seconds his neighbor is looking at cards.

I tell the player the first time in a loud enough voice so the other players and the dealer know what is going on. I'll say it again in an annoyed voice if the player fails to correct themselves. I do not agree that I should have to look away.

If a player flashes his card in his line of sight, and continues to do so after being informed, that's on him. That's also not what the OP was talking about. He specifically said that because of his need to move, he can sit in a way that consistently allows him to see his opponents cards, but he only chooses to do so if he is out of the hand.

If you take any action that you would not otherwise have done in order to see a players hole cards, that is on you. No one is saying that you have to avert your eyes if a player is flashing his cards, but that you shouldn't actively try to look at their cards (even if the action is as subtle as shifting in your seat or turning your head at just the right time, things that you might do anyways-if you do anything specifically to see cards, you are cheating).

You can't ascribe perfectly innocuous behaviour, such as looking to your right or left side, as cheating. That is supposed to be on the same level as swapping out a card or having a dealer cold deck someone? I don't think so.

If you do it with the intent of looking at a players cards. It is cheating. Full stop. I am not talking about accidentally seeing a players cards, I am talking about someone who does something, even if it would otherwise be an innocuous behavior, specifically to see another players cards.

You seem to be equating behavior that can be proven to be cheating and cheating. I am not saying that I could prove you are cheating, I am just making sure that you understand that you are cheating. If you turn your head a certain way, even if it is a movement you do often, specifically to see a players cards, you are cheating. Is it cheating to the same degree as swapping cards or fixing a deck? Probably not, but I don't care. Either you are a player with integrity or you are not. After that, the degrees do not matter to me.

I reiterate there are up to 8 other players at the table. I am more interested in protecting them than the flasher. They are innocent and have almost nothing they can do to protect their interest.

That is why I contend even seeing flashers cards and not informing the table you did is at least a mild ethical issue. Some would go farther and say it is even cheating.

Poker is a game of information and flasher is providing you information no one else has. It affects everyone and n the game

There is no such thing as "looking" when it comes to seeing another player's hole cards. There is only "showing". I warn someone one time that I can see their cards. After that, I silently use the information against them. Obviously I never go out of my way to try and see them but if you're showing them to me, I'll take a look.

This thread is talking about something different. Yes, if someone flashes their cards in your direct line of sight, you aren't actively looking at them. But the OP described shifting in his seat and choosing to look at cards.

If you actively look at a players cards, even if it is as innocuous an action as turning your head to the left or right at the right time, this is a hugely different case than having cards flashed at you.

Regardless of any stretching or movement that a play may make at a table, each player is responsible for ensuring that no other players see their hole cards. It's one of the fundamental rules of the game - "all players must protect their hand".

There is no looking. There is only showing.

Sorry wrong. There definitely is showing. But there is also looking. Player does have responsibility to protect his hand. But ANYTHING someone does to try and improve their chances to see others cards is unethical at least.

Players showing cards to each other while in the hand is collusion in my book.

Even if there is only one showing. What if a husband and wife were sitting next to each other and every hand the wife showed her cards to the husband, even if he were still in the hand? Even if everyone at the table knew it was happening, wouldn't you still consider that cheating?

Showing is cheating. If you don't report the showing, you're enabling the cheating. If you're getting benefit from the showing, it's unfair to the other players (whether you want to consider it cheating or not).

That isn't what he is saying. He is saying that since the player is responsible for protecting their hand, any ability of another player to see that player's hand is the first players fault for not protecting their hand. It is a dumb argument, and can be use to pretty much justify any cheating.

It is mostly the first players fault. But collusion has to be stopped even if only one player is causing the problem.

That is what I'm saying, but I don't see how it be used to justify other forms of cheating.

Players are responsible for protecting their hand. Why is this controversial?

What is controversial is the implication that this absolves other players from guilt or sanction if they take active measures to try to see other players cards.

Whether or not a player is responsible for protecting their hand, that doesn't mean that other players can take any actions they wish to gain info about other player's hands, any more than it means you can wing your discards into other players hands to try to kill them, purposefully act OOT to try to get their hands declared dead, or any other behavior which is generally considered to be unethical or cheating, or even just bad for the game (in the opinion of the floor or desk).

‘Protect your own hand’ is not controversial, extrapolating that to ‘therefore there is no such thing as looking only showing’ is silly and wrong.