Spaceman Spiff wrote:
They must hope that some people are shelling out cash to see the movie just to see the trailer, but I don't think that's all that common these days.
In my local newspaper, the ad for The Day The Earth Stood Still had a little splash ad addition that took up the bottom corner saying; "The only place you can catch the world premiere of the trailer for X-MEN ORIGINS: WOLVERINE!"
So yeah, they think it helps.
I used to go see movies I wasn't completely interested in to catch trailers in the days before the internet, but nowadays, I can wait until Sunday or Monday to see it on the nets.