Isn't what the theater is doing the equivalent of stealing from the producers of "An American Carol"? Wouldn't that be prosecutable from the movie producers' point of view?
It is a French releasing company from what I hear (shut out by Hollywood?).
They should request an audit of the theaters.
Knowing the stunts they pull in bookstores, it is quite possible.
Also make sure that you get 2 stubs back from DIFFERENT tickets if you give them 2 tickets. Sometimes ushers will tear one ticket in half, hand out both halves to the couple, and then shuttle the untorn tickets up to the box office again. No particular slight against one movie, just an underhanded way for the box office worker and the usher to make some money.
Sometimes they will also punch reduced tickets and charge full price. Look at the digital display when your tickets come up.