text: Put your hands over your eyes and claim you are invisible? Actually it would depend on the layout of the theater.  One large megaplex local to me has a hallway where people exit and if you walked in through the doors while others were exiting you'd never get caught unless someone asked you for your ticket.  They key I've found to anything shady like this though is to act like you belong there and know what you are doing.  Do that and you can accomplish almost anything.