Hi there, it seems like a nice system. I have got couple of questions though.

1. Are there implemented any special rules for gateways, or is this just something that everyone can do?

2. Is BTC issued by A and B the same currency? As they may have different exchange rates, I think they are different. But it seems that when a payment goes through the system, they are treated as the same BTC, right? Or are users supposed to set exchange rates between various BTC? Probably they should; e.g. if I think that BTC issued by me are much safer than BTC issued by my friend, then as a payment goes through us, I would only agree to issue 0.9 BTC for receiving 1 BTC issued from him. What are the intentions about this?

3. What happens if there is a debt but no trust limit? I managed to buy some BTC but without extending a trust limit to the seller issuer first. Also it appears that some orders could be created with similar results. Other way to get into this situation is possibly to remove the limit after the debt exists. Shouldn't this be restricted somehow? Or should it be not restricted and the trust limits would only be informative? Actually why should I pressure friends about settling their debts at all? It may be something about that they can't pay me anymore, but hey, I could extend their trust limit further coz it's just a number?