I agree. I guess I am a bit concerned about disputes where you don't have a hard copy of the bill they actually sent you or gave you at the point of purchase.

I agree. I guess I am a bit concerned about disputes where you don't have a hard copy of the bill they actually sent you or gave you at the point of purchase. But as I think about it, there are already third parties who keep records involved in transmitting things already and not many disputes of the type I was imagining. One can imagine how things might be abused, but where the legal system is functioning, there shouldn't be a problem. And if its not functioning, there are much bigger problems. So you're correct.