Its a tough call to make. Obviously the biggest mistake made here was by the dealer. People here seem to place the second blame on player A for not correcting the dealer. I agree that he has a responsibility to do this. But no one here seems to place any blame on player B. It seems to me that Player B shares some blame as well, after all he asked how much the bet was and then accepted the dealers answer even though it had to be obvious that the dealer had not actually counted the chips. he may be least blameworthy but he does have to share in the blame.

Since the consensus here is that the original bet should be reduced to the amount announced by the dealer, let me ask you if you make the same ruling in this scenario.

Player A announces pushes out a single stack of red. Dealer does not break down the stack, but announces the bet as "$100" Player B calls. It turns out that Player As stack in fact was $105.

Should the bet now be reduced to $100?

If not? why should this be handled any different than the original case? Is it based on the amount of of money? If so how much is the limit? Would it make a difference if the chips were $1000 chips instead of $5 chips?