Right, You implemented trade system, it is sound good! but additionally we need for micro transactions a bit more advanced trading,
I was scammed by clan chief/leader by sending to him item over auction for $G1,
to pervert kind of "indoor transactions" we need additional system for trade, I would call it an "hire",
simple add item to auction or trade to person but limited time period,
$G1 for a week to try it out, but difference is, game mechanism will pervert/stop to scam me as after expire time/date item will return to my mail.
simple-practicable-good