When given the 2 seats from the stadium on Christmas Eve eve eve eve, Paul says that seat 15 was his, and 16 was his wife's, yet in the clips at the beginning of the movie, Paul was always sitting in 16 and she was in 15.
When the whole stadium gets hats, they are told to look under their seats for a surprise. except the seats fold up when not being sat in (as shown earlier in the movie) so people would've seen something on the seat bottoms as they arrived.