Well, Bob Greenblatt said it is happening, but I'm surprised Neil and Craig would agree since they spent so much time being very "Oh no, we won't be doing that" especially after Grease Live!
Greenblatt teased that audience members would be part of the Hairspray Live! broadcast, as Baltimore locals and part of the audience of The Corny Collins Show. “They’ll be inside the story as opposed to just bystanders,” said the TV executive.
“We’re going to have people responding in certain scenes,” revealed Greenblatt. “I don’t like the idea of people sitting against the wall or in bleachers applauding. We’re going to work people into scenes, like crowd scenes and extras and background people. They’re going to just organically react to the musical numbers. There will be a fair amount of live responses.”
http://www.playbill.com/article/exclusive-hairspray-live-to-feature-live-audience-and-new-songs
"Anybody that goes to the theater, I think we’re all misfits, so we ended up on stage or in the audience.” --- Patti LuPone.