i think it all depends on who's working.
we always go to the same arena, cuz they are cool with it. the first time we set up, they came up, checked it out, and were pretty impressed. we set up a banshee bungee pulling in to a rail and small jump. one of the guys who worked snowboarded, so he was stoked, the other was just chill. we've been every saturday, and they now even dump the snow where we want/need it !
last saturday, the cops rolled in to see what we were doing. once they figured out we were just skiing/boarding, and that the arena dudes knew, they just said it was fine and left.
just try it, the worst that's gonna happen is they're gonna tell you to leave.