But sometimes audiences just screw everything up: (skip to 2:25, I tried to embed with the time specific URL but it didn't let me.)
I'd say keep the audience out unless you have a really really good reason to have them in there. Like, if they are awesome.
Honestly, I'd say that Linkin Park trying to do an acoustic cover of an Adele song is far worse than the audience failing to clap at the proper tempo.