I would hazard to guess that serious movie goers are more likely than others to go alone. We're not looking for a social experience and indeed that can inhibit viewing the film. For God's sake, you could end up going with a movie talker. Plus, who knows where they're going to want to sit and they may want to leave before the credit finish (blasphemy!).
Not for me. My wife knows how to watch a movie. We have preferred seat locations and once the films starts we are alone together.
Another thing the episode got me thinking about was Saturday night at the movies. That's the worst time to go unless you've picked a less attended or a movie that's not hot hot hot. Lots of young people, dates, and casual movie goers on Saturday nights. Yak, yak yak.
My exception is the Pacific Film Archives in Berkeley, which is about the last place in the world people you'll ever hear people talk. And they do NOT allow food in the theater so you don't have to worry about pop corn chompers. (That's something I just don't get: spending exorbitant amounts of money on food that's bad for you. I've even seen people miss parts of a film buying the junk. You get the same deal at the ballpark.
Anyway, unlike my good friends on Seinfeld, I never have to worry about trying to meet people at a movie theater on a Saturday night. I'm glad they did though, it was worth some more yuks.