LTS:

"Not allowed" and "illegal" are different things, possibly arising from different authorities. It could well be (unless you know otherwise, which you didn't quite say) that the rule was one from a particular theater owner, a theater-owners' organization, from the actors' union, from church or other community organization pressure, or even just a general sense of what was a sort of theatrical common law. All of which could add up to "not allowed", while not being "illegal".

Dave Oesterreich