I don't know the rule here either, but that's besides the point.
Bioware shouldn't have to "protect" us from that. They've given us a "safe trade" way and a COD mailing system for a reason. We should use them to avoid situations like the OP described.
Woah, there is a cod system in place? All this time I had no idea. When I was trying to sell a cyan crystal the other day some asked about cod, I thought they were kidding. Off to do some research I guess. Learn something new everyday, thanks.