In LA a man once owned a 35mm copy of Star Wars. He was a private collector of 35mm prints and had converted his garage into a screening room. The neighbourhood kids would sometimes gather in his garage and they would be delighted to a private screening of Star Wars, back in the days before home video was common. Somehow, wind of this caught up with Lucasfilm/the authorities. The print was confiscated and the man either jailed or fined, i can't remember.
The laws have sort of changed since then in light of the explosive growth of home video but its an interesting story nonetheless. I would say if it is a privately held screening then there is absolutely no problem with it--if it is a 35mm print then some complications may arise, especially if it is popular and the print is not a legally-obtained one (which it likely will not be).