As I understand it, the workers will turn themselves in after their allotted time and return home for a period and then return here again. At least that is one of the three programs I am aware of. It may not be the president's.
The carrot for cooperation is to be able to become a citizen after five years with good behavior. The stick is for them to be returned and not allowed to return if they don't cooperate. The problem is finding them and catching them. That is why controlling the border is still necessary.
Once such a program is installed it will be back to where it was before the massive influx, some cooperating with the system to become citizens and some being outlaws. The idea is to provide a conduit between willing workers and sponsoring employers.
Thanks for the information in your post #46. I could see myself supporting a guest worker program, but my support would be conditioned on knowing all of the details, both large and small, of the program.