Not being an attorney but I do not think there is really a time limit and if there was it might be months or years and not hours.
I have/had family members in table game management and many times dealer errors are caught upstairs but because of the time delay involved the pit might just be notified and do nothing about it. This happens especially when the tape is being reviewed for whatever reason.
When caught immediately it is easy for the pit to walk up to the player and explain that he was paid on a loss or push on the previous hand and he can even have the dealer (dealer had better have put the cards in the discard pile correctly) re-create the hand as proof.
The problem comes when it is several hands later or a new shoe. The pit knows that there is a strong chance that the player will say he does not remember, true or not, and now it is just his word against the eye's word.
So, when it is an unimportant amount of money they just forget it, especially if they are smart.
In the case of Pete Rose and the amount of money he was capable of losing in a casino. $2,500, if caught late should have been forgotten (the dealer will get punished though) but if was caught immediately, Rose should have returned it with the lame, "I did not notice it" excuse we all use.
ihate17