How is it being illegal relevant? Everything cops arrest people for is (theoretically) illegal.

If you're implying that employers of illegal immigration are hard to find, it's really not. Any farmer who receives subsidies (which is most of them) has to submit all sorts of paper trails, and if they have both no employees and no fancy farm-automation equipment, then it's pretty easy to check if they have illegal immigrants.

Hell, a single surveillance drone during harvest season could do 90% of your work. Work you're already doing if you're looking for illegal immigrants. "Gee I have no idea why a bunch of illegal immigrants harvested all my fruit for free", yeah pull the other one.

>and if they have both no employees and no fancy farm-automation equipment, then it's pretty easy to check if they have illegal immigrants.

That's not how it works in practice. They use someone else's SSN and proper withholdings so nobody's the wiser unless the owner of the SSN being used both gets audited and has some portion of their income bumped into another bracket, which is rare.

Many countries do it, with random controls such as statistics checks (like revenue vs employees count, compared to similar businesses) and random visits.

This does not eliminate illegal labor completely but significantly reduces it.

First, the word you are looking for is "disingenuous."

Second, I disagree. It's important to disincentivize both the supply and demand. Right now, employees of illegal immigrants suffer no negative consequences when caught... so they keep in doing it. Which means that these mass deportations are purely performative, and the next wave of immigrants will get the same jobs.