If I'm not born American, I suppose the right way of handling that would be negotiating a date to voluntarily leave the country (I think it's called self-deportation), which leaves you a bit of levee to put your things in order. If I was born American and I only have American citizenship, that would be a strange situation to be in. I suppose a bunch of other countries would have offered me instant citizenship just to spite Trump. I'm not sure what does it have to do with people who entered the US illegally and were never citizens in the first place though.