The collapse would come from a loss of trust from USDT holders who would then try to dump their positions (basically a bank run) for less than their pegged valu

The collapse would come from a loss of trust from USDT holders who would then try to dump their positions (basically a bank run) for less than their pegged values. SEC action could be a cause for such a loss of trust, but you can imagine many others, such as leaks (of damning information) from insiders, other exchanges unlisting USDT, and so on.