By TJ I mean tap jump lol.
I'm not exactly sure how risky the pivot the pivot BB is. Initallty I thought, they can just jump and aerial you, but then I remembered that you'll be right next to them on the edge, so they probably won't hop up, because they'll expect you to them immediately hit in their jump frames (I always used to spike people with Ganondorf like that), so they'll probably go for the GUA.
I'm trying to think of the worst thing that could happen. They could hop-aerial, but as I said, I think it's unlikely given the fact they'll expect you to intercept that. They could just hang on the edge, in which case they get either a free GUA or aerial on you. But at the same time, you can then just dtilt them next time, if they're anticipating the pivot BB again.
By the way, if you BB to the ledge, whilst someone is on it, does it knock them off?