not clear if it is the easiest target to short, given that many people who use tether are fairly skeptical about how/if the tokens are backed by assets but use it anyway (if the recent Bloomberg story is accurate).
Nearly all of the smart contract loans are over collateralized, so collateral > borrow isn't too hard to achieve...but yes, probably only likely in crash if collateral is another stable that holds peg.
Just to be clear, I think shorting Tether is a bad idea lol