Sure, but that's irrelevant as far as the scam goes. What matters is real money entering the markets for fake money, e.g. USD for cryptos. That people after that can trade back and forth between different fake moneys is irrelevant, although it naturally keeps the illusion alive that these are valuable assets. USDT stands out because it's marketed as almost the same thing as USD, which it of course isn't.
I also do think Tether is dodgy, but even if they weren't, the illusion would be the same – real money enters the market through the usual fiat onramps, then it gets traded for BTC. Since BTC/USDT is one of the most liquid markets, this often can result in new Tether being issued to trade with (potentially in a transparent way to the user) and as long as the other party does not redeem these new USDT they inflate the market cap
The question then becomes whether the fiat going in matches the new Tether being issued, and that can't be answered without a proper audit.
