> Anyone who "notices" should make it all fall apart instantly.
This is the flaw in your logic. How would you make it all fall apart? You have to force Tether to make good on more of its liabilities than it can make good on, but very probably, most of the people to whom Tether is liable are themselves drinking from Tether's money-printing trough, and it's not in their self-interests to pull the rug out.
To make Tether fall apart, you probably need to force an outflow of most of not only its hard currency reserves, but that of everyone else feeding at its trough. That is not an insignificant amount of money, and exactly how much is literally the $1M question.
If they are insolvent, then not everybody can get their money back, which means that you should take your money out immediately no matter what you expect other people to do. It follows that you can expect everyone rational to do the same. It's not that anyone chooses to "make" it fall apart, it's that everyone who finds out their secret should independently participate in making it do so and that reinforces itself.
This contrasts with a bank run on a solvent institution, where you only need to rush to get your money if you think other people will too and they will fail due to lack of short term liquidity.
This is the flaw in your logic. How would you make it all fall apart? You have to force Tether to make good on more of its liabilities than it can make good on, but very probably, most of the people to whom Tether is liable are themselves drinking from Tether's money-printing trough, and it's not in their self-interests to pull the rug out.
To make Tether fall apart, you probably need to force an outflow of most of not only its hard currency reserves, but that of everyone else feeding at its trough. That is not an insignificant amount of money, and exactly how much is literally the $1M question.