Would this work sortof like the Trader Rating system?
Like a little tag somewhere that indicated that you were a signed and participating member of this system?
That'd be awesome.
It'd be nice to be able to engage in a sale with someone who you knew right off the bat was either willing or not willing to participate in that kind of action.
It might give you an idea of who was really (in the long run) a reputable, safe person to buy from.
I have a feeling it'd be one of those things that would never have to be used if it was working properly...