And it pre-dates smart phones. My first encounter was a young woman who was texting throughout an entire show. She was near me, and the green glow of her phone was distracting. I could barely focus on the show.
Worse, her mother was totally enabling her, asking about the texts. The only sane person in the group was the grandmother, who at least seemed ashamed of the behavior. It was an expensive show, too. I don't pay $100+ for tickets to have to deal with a spoiled brat on her phone. This was a while ago, but I think I mentioned it to them at the intermission or at a break, and she stopped.
Not long after that, I had to deal with a couple filming an entire concert. That show did NOT have an intermission but afterwards I told them they had ruined the entire show for me because it was hard not to watch their video versus the actual show on the stage. They were honestly shocked by my complaint, and wanted to know why I didn't say something sooner (putting me in the wrong, as you can see). But when could I have? I didn't know about their self-entitled bad behavior ahead of time and there wasn't an intermission, so they got away with it.
Just turn your phone off at a movie or show. It's not hard. I do it every time.
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