Revealing mistake: When Lassard starts spilling golf balls from his golfing bag in the airport, look closely. Lassard is activating some sort of trigger/handle mounted on the bag to release the balls.
Revealing mistake: When Hooks is carrying out her 'crowd-control' sequence, she causes the crowd to step back into a pool. However if you look closely, not all of them fall into the pool by accident, as a few turn round and deliberatly step forward into it.
Revealing mistake: Near the end of the film where Proctor kicks the chair towards Harris, if you look closely you can see the two grooves/rails that the chair slides along.