Again, yes and no. admin is a huge burden; much larger than most realize.
It pretty much comes down to hire Mexicans for the work or no one as no one else is applying. I comply with the law. As far as I know they were all legal. Did I have my doubts? Sure. I also suspected some of them used drugs, engaged in sex with minors and a myriad of other things of which I do not approve. They didn't do these things at work, so it wasn't my job to police it.
If you can lose your business because of it, then it is your business to know it.