We would follow the Idea of Tether and TrueUSD but instant of staying on one fiat currency we would add more fiat currencies for more people around the globe.
The concept behind tether is already broken. Bitfinex and its shills are making sure to promote it but then the infinite supply of tether which can no longer be audited it without doubt a big black spot in the crypto community. What they are trying to achieve is not what crypto was made for. What their intention of doing so could be manipulation of prices like 2017 bitcoin pump and maybe more coming in future.
And yes they can declare it as "illegal" but does that mean we need to stop what we are doing? No.
Yes because they will send their law enforcement against you. If you get into legal trouble with a government you will have to face consequences and so will the people using it.
People can still exchange their currencies and withdraw them 1:1.
They would no longer use it because of their personal loss and nobody would want be involved once it has been declared illegal.