I *was* responding to what you wrote. You seem to think that given a legal and an illegal option, people will always choose the legal option. There are other factors.
I think that we have to give immigrants only one option - legal immigration or none.
No, again you misread me. The "always" is your insertion.
I said that if government turns up the heat enough, it will start to push more people into the legal channels, and that will have a positive-feedback effect.