USDT is on a major exchange and that means USDT is trusted by everyone so it can't be a scam. besides USDT is widely used by everyone to secure assets when the market is red.
There was only a small chance for USDT to be exit scam project consider it's not totally transparent with the real money that has already used to backed the token. I think that it's wrong to call this as a scam. All people trust usdt