Most chains now are represented by an agency. I have been contacted by them many times... for what you pay, for what you get back in return I've felt it wasn't worth the money.
I've always felt that you must base everything you do as a cost vs. return.
When someone is sitting in a movie, and watching your slides, are they going to rush out to a computer for info? NO they're about to watch a 2 hour movie, and when they get out they talk about the movie and go home.
Most of the time WHEN YOU go to the movies, do you make it just in time to see the previews or are you sitting in the theater watching those slides.
I think they could help your business, but for what they're charging for them I don't think its worth the cost vs. what you'll get back.
Just my thoughts.