It isn’t a big deal if they ask politely and a seat is available, that isn’t going to mess up my view of the movie.
What is bad theater etiquette is taking out your cell, phone, tablet, etc. & texting in during a movie while you device screen flashes light in other people’s eyes. Had one idiot do that during a movie and they keep during it even after being warned not to by the manager of the theater hat the device was preventing people from watching the movie.
Another bad etiquette thing is telling the person next to you that they better not eat any popcorn, etc. while they are sitting next to you as soon as you sit down..
I had ticket for an AMC Fathom event and as soon as I sat down once. This woman who I’ve never seen before, said to me, “You better not eat any popcorn or anything else as I want to be able to hear everything.”
This rude stupid hag during the showing was talking to her friend and made a good bit of loud noise during the showing
Also, just about every one in the theater had a small popcorn, as that was free to AMC Stubs members that day via an email coupon.
In most cases I don’t go see as many movies as I used to, as was pointed out earlier you can buy a copy for about the price of a ticket or two when it is released. If your willing to wait a bit longer after it gets released on DVD, Blue-Ray, etc. that you can find it marked down to half the price or even less of what it was selling for in most cases.