I went last night with my granddaughter. Just printed out the paper tickets and showed up with the paper. They don't sell tickets at the door since it's a promo this week. The theatre was fairly empty. I was surprised at how empty it was. It actually made it quite nice to see it in a mostly empty theater. And since the movie was free we also saw The Boy Who Would Be King. Really cheesy but the thirteen year old loved it.
I was able to do this and it was fun! The theater was basically full but for the 1st 2 rows. It was kind of annoying since it was a theater with assigned seats so you had to stand in line and get a regular ticket one you arrived so it started a little late since so many were in line for the additional ticket.