Well, that's in THIS solar system... think about the rest of the universe. Black holes consume 100% of all the mass they encounter. I think they need to occupy black holes.
Besides, I don't think Sol would like that very much.
I wonder if all of the vagrants showing up at the "Occupy" events is coincidental or a clever move by the opposition. A pile of well placed posters offering free food, cameras, wallets and cell phones would bring more than a few in....