If I tell you that I am a Nigerian Prince and that I definitely have a billion dollars somewhere and that you need to just send me a small sum of 10k to release that money, would you not tell people that it's an obvious scam?

I mean you don't know for a fact that I am NOT a prince right? And if you ask me for any documents I'll just say they got lost or it's too difficult to produce them.

In this case the absence of information is the proof that you need to say that tether is a scam.