I never want to be the type of person who goes on vacation and then while on vacation goes to see a movie at a movie theater. I'm sorry, but you can see a movie at home when you have nothing else do to. Why would go see a movie when you are in a new and exciting place?
There might be an exception to this rule of 'no movies while on vacation'. If it's raining and you absolutely cannot go outside and do some exploring then maybe you could go see a movie. However, I think your time would be better spent creating a scavenger hunt in the rain and meeting strangers along the way. OR you can watch a movie while you are on vacation if you are on a plane. These are the only two exceptions.
And then, when you return from a vacation where you went to see a movie... don't let that be the first story you tell about the trip. Furthermore, don't try to tell everyone else what happened in the movie. Don't be a scene spoiler!