There is indeed a distinction between your own private property and a business that invites the general public in to do business. The cinema is still private property, but it's still also public space.

That said, I don't think anyone has ever attempted a ruling on whether chicken wire/Faraday cage in the walls of public spaces is permissible according to the FCC. I'd doubt such an attempt would make it far; there are so many buildings made with metal siding which do a fantastic job of reducing cellular signals to useless levels.