Players and dealers have a responsibility to everyone at the table to make sure that the bets are correct and understood. If a player says he is all in, then all of his chips are included, even the hidden ones. I think if a mistake is made, then the mistake should be corrected and resume the betting for that round. If it was a gross error by the dealer that causes a player to bet the wrong amount, or the action was unclear, then the player that took action under those conditions should have every option open to him. That includes retracting a bet. The rules for poker were written to protect players from collusion and "trickery." The only way a player holding the best hand should not get the pot, is if he were bluffed out, not robbed by some technicality.
That's the way I see it.
Nick C