The best suggestion I've seen below so far is saying "only the recent rewards and among your fireteam" but even that could have dupe-issues. Adding a trade system pretty much guarantees a few months of Item-Duplicating as some bug will trickle in. It happens in most games when they add it, and usually takes a while to patch out. During that time the economy goes to hell, everyone is running around with the best gear possible, etc. It also opens up the door to gold-farmers and black or gray markets. Which obviously gets annoying, only at least here we don't have to worry about hearing / reading spam in the game "CHEAP GLIMMER AT StealYourCreditCard DOT UK" or whatever Then even without duplications, you'll still have people getting the best gear and blocking people who aren't "dedicated" enough to the game to have it. Imagine the whole GHorn situation prior to the recent Xur selling, only 10x worse.