I had a friend who often got photos with actors at the stagedoor after performances, and would also take photos at the curtain call. This was past flashbulb days (remember the rotating cube?) but pre-digital cameras. There was a chance you would be required to hand over your roll of film if the ushers were strict. I believe she carried an empty roll in per pocket in case she was required to turn it over, but don't think she ever had to.
I do remember one time during the Cumming/Richardson run of Cabaret she took a photo at the end of the performance from the front mezz of Cumming in his striped camp uniform with pink triangle. I don't think I was with her for that performance, but when I saw the photo, I admonished her for taking a shot at that moment. She agreed in retrospect that it was bad form. That image is still burned into my memory.