It totally depends on the show and performers. A lot are very gracious, but not all...and like anyone doing anything, it can vary depending on the day and life events.
As far as leaving the show early, unless it's something where people are being absurdly fangirl/fanboy-ish (a la when Adam and Anthony were back in
Rent) I have never had a problem getting a spot waiting until after curtain call to leave.
Experience live theater. Experience paintings. Experience books. Live, look and listen like artists! ~ imaginethis
LIVE THAT LESSON!!!!!!