That works for me! The only other thing I'd ask you to consider is human nature. The rules you laid out are fair and sensible and everyone who signs up would be agreeing to them. But...nobody likes being rejected. If somebody keeps getting their offers rejected I can see people having a lot of hard feelings. Some might take it personally. Others might just turn sour on the entire idea of swapping because they couldn't get most or any of the seed they wanted. I have no idea how to handle that situation. When people get emotional logic goes out the window. Same goes for banning people. You'd have to be very specific on what actions can get you banned and how people can get reinstated. How private will the process be? I can see accusations of unfair targeting being brought if everything is kept secret. You can probably tell I'm a worst-case scenario type of person. It probably won't happen, but it could get ugly if it does.
