My gut feeling would be to call a misdeal mostly because 1: I work corporate events, not in a casino, and therefore I come across very few rules nits but more importantly 2: the hand will have no doubt degenerated into such a shambles by this stage that I'll be left with no real choice.
This is a weird situation though, and I don't think it's really dealt with adequately by the rules. For example, it doesn't fall into any of the categories where Robert's Rules say you can call a
misdeal so my gut reaction would, it seems, be wrong.
It kind of falls under
Irregularities rule 12, which says that a card flashed by a player must be played (ie: it won't be replaced like it would be if it was exposed through dealer error), though I
know that rule is intended for cards flashed or exposed by a player in their own hand, not necessarily someone else exposing a card from their hand.
Note also that the rules cited by fletchdad don't address the situation adequately either because they talk about the player having no redress if your hand is fouled or accidentally killed. This hand hasn't been accidentally killed though. Whether it's been "fouled" depends on your definition - I've always assumed it meant a hand where someone has folded their own hand near yours and you can no longer tell whose hand is whose any more... though thanks to this post I've actually looked at the definitions and Robert's Rules unhelpfully defines "fouled hand" as "a dead hand", which is irritating circular logic and doesn't help us. Suffice to say the rule doesn't give us a clear answer and if applied would actually be in contradiction of Irregularities 12.
Lastly, Player B's
actual hand shouldn't be killed because
it doesn't meet any of the criteria for being a dead hand.
So... congratulations. Unless someone can find something that I've missed in the rules, OP has dug up a situation that exists in a fuzzy grey area between several rules and isn't properly addressed by any of them.
If a TD or floor manager was called over to make a ruling on the situation, I expect it'd go something like this:
- Player A's hand would have to be exposed to the rest of the table, since one player has seen it through error and the rest of the table shouldn't be denied that information.
- Player A will then almost certainly have to fold when it's their turn to act since the whole table has seen their hand now. It sucks and it's no fault of their own, but them's the breaks.
- The rest of the table plays the hand out as normal. Player B may or may not get a penalty at the end of the hand.