If Player A bets the same amount as Player B (agrees with the OOT), are you saying the out of turn can still retract his bet? If this is correct, then the only way to assure the OOT stays is if Player A checks?
That is correct. I wouldn't be so hasty to change that though. I don't think you are thinking of the negative consequences to Player A. Keep in mind that Player A does not always want Player B in the hand! The only way Player A can get B to fold is by betting, correct? Yet, with your proposed change, Player A would have to
raise in order to have a chance for Player B to fold.
By trying to penalize Player B, you could be penalizing Player A...but there is no way for you to know. In limit poker especially, the more of Player B's money that you force to stay in the pot, the less likely Player B is to fold...which could be positive
or negative for Player A.
Better, in my opinion, to give hand/orbit penalties if you feel there needs to be more of a penalty for Player B.