Near the end of the movie, when Greg is in the airport, he approaches a flight attendant, who denies him the right to board because they are not boarding his row yet. When it shows him from a point of view which shows two computers to her side(It happens a lot, don't worry, you'll have lots of time to spot it) The computers have a special sticky thing on the blank part, to make it look like the computer is on. One of them is crunched up, allowing you to see the black!