I think that's sort of the idea behind the lawbreaker powers anyway, only a more forceful in their case. The more you break the law, the more you are drawn to do it again, therefore you have less free will, represented by less refresh. If you are forced into lawbreaker compels via debt, it would effectively be the same thing, without forcing the character into NPC territory by lowering his refresh.
Though I wouldn't attach any actual power to this. Or maybe a [-0] power, just to have it written down somewhere. It would basically be a debt on the characters lawbreaker aspect (which should be there in any case, I think).
I like it.