psyduckster and ottery: Great point about choice. I think you're right and that is the defining feature.

redboy: i dunno. I think there is a difference betwen choice and conscience. (Pinoccio (sp?) didn't have a conscience but made choices). i don't think Petigrew's choices have been defined by conscience at all. Indeed, i wonder how much conscience Peter has. I Do think that his choices and actions have been informed by consciousness which is typified as self-preservation and spite.

In GoF we are told that Peter is revolted and he "flinches and shudders" (Aus,hardback, p14) at
'the thing Wormtail had been carrying [which] had the shape of a crouched human child, except Harry had never seen anything less like a child. It was hairless and scaky-looking, a dark, raw, reddish black. Its arms and legs were thin and feeble and its face -no child alive ever had a face like that -was flat and snake-like, with gleaming red eyes- ... and Harry saw the look of revulsion on Wormtail's weak, pale face...' (pp555-6).
Sorry but what here, or anywhere, implies that Petigrew doesn't want to be bad??
He wants to be anything that sees him stand out in a crowd, get one over his condescending friends AND gets him power and glory.
There is nothig loyal or thoughtful or, in the least , loving, about Petigrew. He is a bad man and always has been. That's why Sirius laughs when he discovered Peter's treachery, because he realised the extent of his nastiness and the Marauders' stupidty in buying it for all those years.

I agree redboy that Peter will help Harry out of a sticky siituation but I don't think it'll be by choice. I can't imagine Peter turning from the darkside now -all a little too late!

So. I think that though a debt may be created by the conscious act of another, the debtor is bound in a very magical/ unconscious way.