When Stan tells the dads that it'll be hard for Steve and the daughters to make decisions on their own, the entire group can be seen to be 16 dads armed with swords. Moments later, there are 65 swords stuck through the closet door. That would mean 65 dads with 65 daughters, 130 people, when there are definitely nowhere near that many people at the party.
In the opening shot within the kitchen, the wall phone is missing.