[cobalt]

Well the most likely "standard" ruling is that players may not expose their cards unless it's the end of a hand or an all in call. Of course in a casino/official tournament, people can be punished for improper play. But in a home game, you'll just piss people off if you try to punish them.

But in home games, the rules should be set by the "house". Thats how we play at my homes games, so if anyone has a problem; I settle it based on what I think is right.

If a dealer exposes a cards, all chips go back and the hand is redealt, but in a situation like this where the SB is really only hurting themselves, I probably would let it play out.