Freudian said:
People abusing the disconnect protection in NL is pretty common.
I've had extremely good success with reporting these guys to support, and having their disconnect protection revoked permanently. Just write a nice email saying the player, the hand, and the reason to believe it was DP abuse (90% of the time, they are on a flush draw, and were on one the last time they disconnected too)
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As far as collusion goes, if they're cheating, they're not doing it very well. Knowing 2-4 extra dead cards is rarely going to have any practical application. Squeezing players out with raises is dangerous since a sharp player can exploit this to his advantage. If the middled player is on a draw, now he's getting 2:1 on every additional chip he puts in the pot. pretty good deal for him!
I'll take a table full of "cheats" over a table filled with observant, thinking players, any day!
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Beyond that, all my worst "cheats" in casinos weren't from signalling, or trapping or anything like that. They were people who abused rules to shoot angles.
In one casino, if a player makes a fouled bet, it can be withdrawn, and fouled is one chip shy... so I bet $100, and they verbally raise to $500, but only put in $475. I re-raise all-in. Then they declare their own raise illegal, and take it back!! (I only know of one club with this asinine rule.)
I had another player who tried (but fortunately failed) to win a hand via technicality... 2/5 no-limit game, very aggressive player in middle position opens to $30. I'm in the big blind with kings, and re-raise to $90. He calls. The flop comes AJx. I check to him, he bets $75 but he looked weak... I thought maybe he had a bad ace and would fold to a raise. So I raised all-in (about $500 more) and he quickly called. Before he turned over his hand I said "I guess you win this one", since I couldn't see how somebody could quickly call without at least top pair... but then he turned over KQ.
He tried (and almost succeeded) in getting the floor to award him the pot on the basis that I'd conceded the pot, even though absolutely everyone at the table (including the dealer) agreed that this was not my intention.
The best casino poker advice I can give you:
Never let go of your cards, until the dealer has pushed you your winnings.
Always be extremely clear with your actions. Count out the correct number of chips, and put them in the pot while verbally stating the action. If you do just one, or just the other, somebody will screw you at least once a week.
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for cheating/colluding in the smaller games of $5-10 and under, I'd say there's just so many games it doesn't pay to worry about it to the point where you're stressing.
Honestly, I just can't imagine anybody having the skills to cheat effectively, and choosing to use them at a 5/10 game. To do it profitably you'd need to know how to play quite well... and at that point, you'd make more money by playing a 20/40 game straight up.