if they find out that the USDT is not backed up to the dollar, what will happen to it?
If this was the case then USDT's days being a stable coin will be over. Tether has been a solid crprotucurrency in terms of protecting your capital in volatility and it had little to no effect to it in terms of its price now that if this happens all trust will be lost and hodlers will imediately sell their position in a heart beat. By the way if you are really clueless to what is really happening and you are interested in answers you shouldn't have a misleading title to catch our attention, that's really an awful thing to do with your fellow members.