Why was the NBA referee going crazy next to the highway?

That's one of the only rules I can remember from being forced to play group basketball in gym. Then I watched some pro ball and I was thinking "Wait, we were told that was against the rules! Why do they get to do that?" I thought maybe it's like the rules for football - a few things are allowed in college FB but not allowed in the NFL and vice-versa. (At least that what I was told by someone who was a rabid football fan, didn't matter who was playing, they were going to watch the game.).