It was common in TN, that before you entered a self-serve car wash, you got out and inspected the bay floor for nails. The illegal alien roofing companies that were everywhere, would pull their P/U trucks into the bays and wash them out, and this would litter the bay with nails. In fact, most car washes had signs banning roofers, but they were in English only, so how were the illegals supposed to understand them.
However, one bright Saturday, when I was getting out of the Vette to check the bay floor, I heard a bunch of Mexicans cussing. I looked into the next bay and there sat a roofing truck, four Mexicans and three flats. I gave them a thumbs up, and laughed the entire time I washed my car, and really laughed when another pickup full of Mexicans arrived and they started swapping out the flats.