My latest job was the first that actually demanded to see my SS card. I've never seen it myself, Dad wrote the number on a piece of paper for me when I needed it the first time. So I asked Dad for my card. He's got no clue where it is.
Went to the Social Security office. Had all the ID I could find with me, including passport.
They told me I wasn't legal to work. I'm a Mexican. True, I am Mexican. Born in the old DF. I showed them my passport, they said cool, State Dept. says you are a citizen, you are a citizen. They update my records, I get my job, all is well. Apparently Dad or Grandpa was supposed to fill out a paper that said "but his parents are Americans, so he is too" for me when I was little and forgot to do it.
My point: I worked 30 years as an official, documented illegal alien. My papers, which I've never hidden, said (mistakenly) "this guy is a ferner, hell no you can't hire his wetback ass". And nobody has said "Boo". I'm suspecting because of my pale hide and impeccably semi-Germanic butchery of the ol' Anglo Saxon sprach.
So, maybe instead of going out and checking people's papers because you fail to realize who the bad guys are when you watch old movies you ought to pay attention to the papers that legitimately come before you.