Revealing mistake: When the Hotel manager walks in the recently vacated room, we see the piano collapse. If you look closely, you can tell that the front two legs were just pulled back under the piano causing it to collapse.
Bachelor Party (1984)
1 revealing mistake
Directed by: Neal Israel
Starring: Tom Hanks, Tawny Kitaen, Adrian Zmed, George Grizzard
Other mistake: In the beginning of the movie, when the mechanic is working on the car on the lift, he says he has to change the oil in it, the chassis drops to the ground, there is no engine attached to the chassis or body. In addition, he is changing the oil at the rear axle.
Mrs. Thompson: I had a wiener right in my hand.
Chosen answer: It's showing he's sexually adventurous, as he's using a cooking appliance as a sex toy.