While moviegoers are long past the days of rushing to the movie theater to make it to their seats before the listed showtime, AMC is now giving a courtesy heads-up that’s hard to miss. Previews and various advertisements have almost always come before movies in theaters, and that aspect won't ...
The theatre I usually go to is an AMC theatre, and they just start the previews however many minutes they take up before the movie starts, so the movie itself starts on time.
Or at least, they still did the last time I was there. Which was only about a month or so ago; went and saw a showing of Monty Python’s Holy Grail for its anniversary.
However, it’s also not fully automated as of yet. There’s a human being who still has to start and stop the thing.