I have a Kinder kid in DCPS, and I would say that he watches a movie about monthly, maybe more often. They have some kind of point system and when they earn enough "points" for good behavior (class-wide), they get rewards - silly sock day, extra recess, crazy hair day, pajama day, and movie day. I hear about it each time because he's always SO excited to have earned a movie. He does say they never have time to finish the movie, so my guess is they watch for an hour.
I do not love this, but MUCH prefer it to iPad time.
There was never any permission side to this, and it seems like the kids vote on the movie. All the movies sound kindergarten appropriate.
Personally, I'm getting involved in Schools Beyond Screens DC because I think this is all waaaay too much, but again, my beef is with the iPad (they also get to play games on it on Fridays! Ugh) and iReady and "brain breaks" that are supposed to be dance parties but are really just kids staring at a video on a smart board (just put on MUSIC for godsakes) and stuff like that. Routine screen "learning" and using screens for regulation (!!) is terrible. A movie as a treat for good behavior? Okay.
https://www.schoolsbeyondscreens.com