This is a tough one, because I don't really see any evidence that Tether is doing anything wrong or that BitFinex doesn't have the tether backed up... but I can definitely understand the lack of transparency concerns. I personally don't like the idea of using USD or USDT on exchanges as a holdable commodity that you arent cashing out, because it creates a shelter for a shelter.. and it creates these crazy Alt - > BTC - > Tether -> BTC - > Alt position trades that I don't think are healthy for the market... but I see no sign for concern at least as of now, and it seemed all created as a plot for whales to move margin exchanges.