This creates an excellent and essentially irrefutable excuse for stopping further withdrawals.
Withdrawals stopped months ago. Bitfinex claim that if you have over $50,000 in USDT you can withdraw it via their special arrangements. I have never come across anyone who's stated this was possible for them.
The most likely outcome for the death of USDT is a shutdown initiated by the US. Tether only exists to bypass regulations. Soon enough they'll punish that and put the frighteners on the exchanges trading it.