the idea being that you create new tether when someone deposits the same amount of USD and when USD is withdrawn from the loop then so should the same amount of tethers. What I dont see happening is the removal of tethers when the USD flows out of the crypto space. Enough people have taken profits at this stage that surely some of those USD should have been used to pay out early investors in BTC, thus some tethers would need to be destroyed to maintain parity. Bitfinex should not even be keeping tethers where they have paid out the USD as they can easily create more when new USD is deposited. if it is a scam I am impressed by how long they have managed to keep it going.