Anybody else ever witness this phenomenon?

I was playing 2NL on Stars the other day and there was someone at my table who would fold their hands and let the pot go to whoever they were heads up against, and most of the time there wasn't even any betting going on for them to fold to. I also had someone at a live 1/2 cash game who would fold his hands out of nowhere the same way.

Why do some people do this? Is there some kind of hidden advantage to giving pots to people for no reason?

There is no reason to do this, after all, even if you have the nut low OTF, you could theoretically have the best hand by the river.

I think people do it when they called pre with something they shouldn't have, completely missed and are embarrassed in case someone sees the junk they played.

Reasons I fold out a hand online...

misclick
no chance of winning and I'm in something big on another table
no chance of winning and I need a slash
no chance of winning and I need a coffee/beer/single malt

In terms of actual play when I might do it...if I've been counterfeited (on the river only) and I don't want to give away information on my starting or 3/4 betting range. For example, I'm 44 in the SB and raise, BB three bets me and stacks are deep enough to set mine. We check/check paired flop and brick turn, river pairs turn and I'm holding 4 high oop. Assuming I've nae chance a split, I might fold here (then again I might not).

I agree with WB when fish do this (and if someone is doing it frequently they are probably a fish) but I disagree there are no valid reasons to do it, so don't level yourself, especially online.

Not sure I'd ever do it live, definitely not the example above, I'd be showing it for the banter (but I'm a rec at heart).

Above reasons are reasonable, I retract my 'no reasons' remark.

My home casino has started penalizing for this in tournaments.

How come?

They rule that folding without facing a bet is acting out of turn. (Even if the action is on you)

It benefits/screws other players for no reasons.

If it is heads up I see no use for that rule; if they were chip dumping one can simply check and fold to any bet. If it is multiway however and I am against two players and one of them may or may not bet(/bluff), if one just folds when it gets to him this player might just change his mind about his action and that could turn out in my disadvantage.

I know some players will just look totally not interested (genuine) and are ready to fold in advance but it's not quite the same because they could reverse tell this. You cannot reverse tell a fold.

If a player was reluctant to show his hand for whatever reasons he could just check and muck at showdown. Most folks won't demand to see your hand if you fold to them. I don't see why the guy would do this live.

I see people open-folding quite often on Unibet. I think they are just inexperienced players that are new to the software. I've had many lolz when I have something like 54 on AK9 and villain just folds instead of checking to me. It's pretty weird, because if you press the FOLD button there is a pop-up dialogue box saying something like "Do you really want to fold? Checking is free", but I've almost mis-clicked on the dialogue box a couple of times, pre-flop in the BB facing a limp especially.