This is one of the reasons I love places like the Alamo Drafthouse, which will outright kick you out if you use your phone during the show.

Holy shit. I haven't been to the movies in about 5 years. Back then we had Facebook but I don't remember ever seeing anyone on a phone during a show

why not just kick out people who use their phones? that's what the AMC where I live does and it seems to work well AFAI can tell. I used my phone to text and got kicked out (I underestimated their resolve) once but now I know better and haven't done it since. If I had to wait in a second line before and after a movie, I just wouldn't bother seeing the movie.