Every time someone walks down the street with a long gun and gets accosted by LE for doing so, it's a de facto prohibition because it has the effect of making people decide run-ins with irrational power-trippers isn't worth the exercise of one's rights.When did they tell him he couldn't carry it in public?
You're right. In the OP's example, they weren't prohibited in the absolute. But a policy that results in nobody doing it for fear of police reaction is a prohibition none the less.