I know this has been brought up before, but how about a new take on this? What if, between families of accounts, you could trade anything between characters, as long as it is not a no trade item? Say, my brother finds something that I could use, because we are under a family of accounts, we can trade. No harm, no foul, it occurs only within family accounts and no other players.
Another option would be to have emails and verification to approve trade transactions, if trades were to expand to more than just treasure cards, and more than just the family of accounts idea.
