This is something I haven't seen in my theater. I wasn't even aware that it happens.
Theater Chain Says No Refunds For Potter Fans
The General cinema movie chain has posted signs in its theaters this weekend notifying customers: "If you buy a ticket for the Pokémon movie with the intention of just watching the Harry Potter trailer, we will not refund your money." Today's (Friday) Los Angeles Times commented that the move reflects a long-standing policy of the movie chain related to the screening of trailers in which there is high interest. In several instances in the past, the screening of such trailers has reportedly boosted the box office take of otherwise lackluster performers, but this is the first time a chain has indicated that some customers buy tickets to see the trailers, then exit and demand a refund.