Not collusion if it is unsaid. Does it really need to be said in late game of a tournament that you should let the low-stack players take each other out rather than risk losing your well-off stack against other large-stack player in an all-in situation?

Or that strong players seek fish and weaker players, rather than saying, "oh, he looks like a solid, tough player, I should focus on risking my money trying to prove I'm better than him?"

These are more of de facto cooperation, rather than collusion.

Even unsaid, behavior in your first scenario is borderline collusion at best. Your second scenario is thought of as smart tournament poker. And people do it because they think it is to their advantage.

I think the difference in the two scenarios, and why one passes the smell test and one doesn't, is that the the regulars systematically behave that way because of their status as frequent visitors to the venue, whereas at the start of the tournament everyone has an equal opportunity to get into the position of one of the big stacks avoiding each other.

Does it actually help the regulars though? It seems to me that it would mess up their ranges - against each other it would increase the value of "marginal" hands by making it easier to take them to showdown but reduce the value of the implied odds hands by making it impossible to win big pots with them. The ranges they play would need to be a compromise between that set of factors and the normal factors in play against the general opposition.

If you are in a tournament and your primary motivation in not playing a hand is that you might get knocked out or crippled, you are not playing to win. You are playing not to lose.

Wrong thinking.

If it's a winner takes all tournament then I agree, it's wrong thinking.

Even in the current, common type of tournament, I think playing not to lose as primary motivation is wrong.

Print money in SNGs then, because lots of people there believe in ICM (coincidentally brought into poker by MM) and stuff like that.

They'll do stuff like jam SB into BB 60% expecting you to call only 15% from the BB but if you are just playing for 1st then you can maximise your chipEV by calling more like 40%.

When the situation is reversed and you know they're only calling 15% on the bubble you can jam any two cards for chipEV.

You will get more 1sts than most people and fewer 2nds and 3rds. Good luck - and don't forget to let us know how you get on.

I have read each volume of Poker Essays at least twice. A lot of the information is quite relevant.

I especially enjoyed the "In the Cardrooms" sections about game management and issues that come up there (which is also important to know from the perspective of a home game host, as well as a profitable player who wants good, consistent games).

Also, as mentioned above, the information about which skills are most important in which games is really helpful, especially when approaching new variants. That may be the most valuable material in the entire series. It has helped me a lot for sure, particularly in dealer's choice and rotation-based private games.

There are other situations that come up in a poker room that might fit the cooperation instead of competition idea. Things such as seat changes and table changes come to mind. Also lists for open seats could apply. The card rooms have different motives (such as avoiding arguments, etc.), but the players (especially regulars) have an interest in cooperating with a fair system so as not to have to waste energy and their attention keeping an eye open for an advantageous seat or table before another player grabs it.