Other mistake: The wedding is officiated in Illinois but the cop car is from Wisconsin.
Continuity mistake: When everyone except Helen start to show signs of food poisoning in the bridal shop, Becca puts her right hand over her mouth to keep from vomiting. The camera then switches to behind her but her right hand does not appear to be over her mouth anymore. It switches to in front of her again and this time, Becca has her left hand over her mouth.
Revealing mistake: Despite her claiming to be topless you can see what looks like a tube top on Kristen Wiig during her attempts to get the state cop to notice her.
Suggested correction: No, she's not wearing a tube-top. Looked up the scene on online. She has her hands covering her nipples, and her passenger Helen has her arm up in a gesturing manner partially covering her breasts, but there's absolutely no tube-top in sight. (I think you may be seeing part of Helen or Wiig's arm and think it's part of a tube-top).
