Crap. These people didn't know because they didn't want to know.
I wasn’t the employer, but I was doing IT work for their HR department when the illegals with the documentation were hired. They presented themselves as US citizens and had documentation obtained through forgery and identity theft. The employer couldn’t use eVerify and as I said, their documentation was better than my own.
HR did what they were legally able to do and ended up hiring them (and several actual Americans at the same time, it was for a new road crew). The only reason they were caught was when the company won a bid for construction on a military reserve and all the employees had to undergo military background checks. When confronted by investigators, the persons everyone had thought to be Americans admitted they were illegals.
And literally nobody could tell they were illegal before that moment.
I realize it’s comforting to think that it’s easy to tell, but for small businesses it really isn’t, not these days. Make eVerify the law of the land and open it up for easier use, *then* you may have a point.