Maybe using an MMO style trading system VIA villagers. Would be more user friendly and you'd be able to physically see the trade before accepting it.
~ @xT3Kx
That's what it is. It's basically a ender chest but for /trade and you put stuff in it.
+0.7
Yes,But then people could quickly grab out the item and accept.
~ @AmericaBabyYeah
Well, I don't think it can work that way. Let's say once I click accept, it's for that deal. If they take it out then it takes my accept away. So when I click accept Teh deal is locked then they can take it out (decline it) or hit accept and trade gets done.