"In exchange, we give some people jobs, but get to tag them and make sure they leave at the end."
Make sure they leave at the end? Surely your not serious. Exactly how would you propose we would do this?
It will be a lot easier than it would be to find them now and deport them.
You won't catch the mouse if he stays in your walls, and you won't get rid of the illegal immigrants if you can't find them.
And while it sounds great to say we'll just fine the employers, you have to find them as well. You can probably get the people employing thousands of workers. You're never going to find the millions of people who have illegals as gardeners, baby-sitters, and maids. Nor will i be easy to crack down on illegals doing day-labor without hurting legal immigrants doing the same jobs.
The guest worker program gives us workers we need, at least in the short run, while giving illegal workers an incentive to come out of the closet. We can't replace 12 million workers overnight, so let's use that fact to help us find these 12 million people.