There is a fundamental shift happening in the film exhibition industry that warrant reconsideration of the above advice ("I can't think of a single reason...").
Within three years exhibitors will have shifted to digital projection, which will allow them enormous flexibility in programming.$4000 reels of film will be replaced by $80 hard drives or satellite transmission. The impact on exhibitors profitability will be the same as if airlines suddenly had planes that could expand from 20 seats to 200 depending on demand.(Have you ever wondered why the turn people away for opening night of Harry Potter but still have some dud running on three screens?) Moreover, it will allow exhibitors to show alternative ("niche") content to fill slow nights (concerts, sporting events, re-runs targeted at special groups). Remember, for all of their cash flow, theater companies run at about 25% occupancy and make most of their money on weekends. 3D is also likely to draw people back to the theaters, if for no other reason than to just see what all the fuss is about. These are heavily leveraged companies, which makes them risky, but amplifies even small changes to the bottom line. For 6% and a good story like that, I'll wait and see how things turn out.
Disclaimer: I'm long on Regal and Cinemark.