There used to be a tradition of practical jokes played on the final performance. It's not professional, perhaps, but there it is. I recall,
quite vividly, at the last performance of A Little Night Music, when William Daniels (who had replaced Len Cariou) moved to start
the automobile near the beginning of Act Two, the car suddenly backed offstage before he actually touched it.
The audience, all (or most) ALNM regulars, immediately caught on and there was a slight wave of titters. But I haven't heard of
this sort of thing on the last twenty years or more.