Would be an interesting movie, it sounds like ... not beholding to either side. But it would show the flaws of our current system ... the guilty are the employers and the politicians that ignore the employers of the illegals.
Agreed, with a couple of caveats.
In a number of industries, a businessman who refused to hire illegals will be quickly out of business, as his costs will be significantly higher than the competition. Either he operates at a loss, or he has to raise his prices, which causes him to lose customers to the competition. If the law isn't enforced, a single employer cannot take a stand by himself.
I am not aware of any effective way for an employer to tell if an applicant is illegal. Asking questions in this area is a great way to fall foul of the discrimination laws.