Told off

Something weird happened to me yesterday, and I’d love to get an outside perspective on it.
I was at my second daytime screening of a French film, this time at a much larger theatre in town, but this one was pretty poorly attended. There would have been less than ten of us in the entire auditorium. I’d bought my ticket online, in the middle of a row towards the back of the theatre. I noticed at the time that there was one seat already taken in my row, but way over on the side by the aisle. When it came time to go to my seat, I had to go past the lady who was already sitting there.
I was just in front of a couple of women who chatted loudly as soon as they sat down, and hoped they’d stop once the movie started rolling.
While waiting for the show to start, I started scrolling through my emails, and I suddenly saw one that was offering preview tickets to an upcoming movie, a yearly event thrown by my insurance company. From past experience I know these screenings sell out really fast, so I set to work buying the tickets while the ads were showing on the screen.
I was at a vital stage of the process when the credits started to roll. “Turn off your phone!” came a stern voice from the end of my row. It was the lady I’d had to get past to get to my seat.
I wasn’t quite done so I pulled my phone closer to me to reduce the light pollution for everyone else, and kept going. “Turn it  off! Now!” said the lady. “I’m just about done!” I said chirpily, finished the transaction and turned my phone off. The credits were still going on the screen, the film hadn’t started yet. The woman who was complaining was twenty seats away from me at least.
The movie was a slow and thoughtful one – the second one of the day featuring middle aged ladies having extramarital sex. When the lights went up, the lady was gone.
So, weird, right? I don’t like people having their phones on during a movie either, but I would never have said anything about it in a hundred years. And the movie hadn’t even started yet. My question is, was she a critic of some sort? Had she raced off to write an opinion piece on the poor behaviour of movie audiences ever since COVID? Was I to be outed as an example of the worst kind of human being? Or was she just some righteous private citizen? Will I ever know?