I could be wrong, but has hasn't the business model for showing films changed as well? Theatres used to rent the 35mm prints by the week or month. Now, studios ask for a cut of each ticket sold, don't they? That's why studios are worried about unauthorized showings that could happen "off the books" and go unreported revenue-wise.
Yeah, the distributors (often but not always arms of studios) take a percentage of each ticket sold. It's usually a sliding percentage- the distributor gets more at first and then the balance slides in favor of the exhibitor (theater) the longer the film has been out.
The big chains are all computerized and report back to the distributors and can generally be trusted to be truthful. It's the mom and pop theaters that might have cheated in the past.
