Cash game. A player is all-in pre-flop for example with 10$ only left and two other players with big stacks call him. Flop is opened and one of the players with big stacks open for example 15$ and other player calls him and the turn is opened again one of the player raise for example 35$ and other player fold. Now my question is: The player that have just taked that side pot that is 30$,can he fold without showing the cards before the river card is opened...for example just to let "the all-in player" to take first pot that is also 30$ ?
Ok so there are two scenarios here to consider, was the fold made on purpose, with the player knowing another player was in the pot, or was it a mistake?
It is not the dealer's responsibility to protect a players hand, if they want to fold they want to fold, especially in cash games. If as a dealer I feel it was a genuine mistake, that they didn't realise the other player was in the hand, I'll give them a warning and we will move on.
If as a dealer I feel it was an intentional fold and they knew another player was in the hand, or they have already been given a warning for this type of thing. I will call a floor staff, explain the situation and get a collusion call made. From there it is up to the floor to decide if the winning player has to show his/her hand to claim the pot.
It's a pretty suspicious thing to do, even if it's not collusion you'll have a hard time arguing against it.
No, regardless of whether its a cash game or a tournament the not all-in player cannot fold or muck at this point. The moment the other side pot players fold the remaining player must show his hand and the cards must be dealt out to the river. This is a rule specifically to prevent collusion, at least its been a rule at every casino i've ever played in.