If that doesn't do the trick and they don't backtrack, and you have to catch a movie at AMC (god help you) just come later. Currently, AMC says the movie starts at 7:00pm, we all know to come at 7:25pm to catch the end of things. If they add 10 minutes of ads, make that 7:35pm. You don't have to see the ads, just don't trust the start time.
AMC has provided a unilaterally terrible experience for filmgoers for years, and they should be ashamed to be one of the primary operators in the country. I love and support the independent cinemas in my area, and when I think of AMC, I think of popcorn-strewn hallways, worn-down seats, and having to navigate a depressing half-dead mall in order to go there. While I'm empathetic to those who only have AMC in their area, otherwise, just go somewhere that actually knows how to run a movie theater.