I am ok with things that keep the cast having fun with private entertainments that neither disrupt the flow nor detract from the story - I have tales from the road - (and clearly, Mr Shiner is a champion when it comes to practical jokes, given the creative and bizarre nature of his farewell from the Shakespeare Theater Company) but anything that affects how our audience sees the show, anything that challenges safety or changes cues or affects another actor's performance - that is unprofessional and unacceptable. As Matt said, these folks have paid good money to see the same show, and for the first/only time, on closing as they would see any other night.