On the drive over from Utah I stopped in Elko, Nevada to sleep for the night, and as I had before I found my "spot" in Palo Alto, I drove off into a less populous street, crawled in the back of my Civic and tried to look inconspicuous.
This time, however, I woke up to a police officer shining a flashlight in my window. After I explained who I was and gave him my license to look me up, he said, "Really you should just go sleep in the walmart parking lot." Since I had to go to the bathroom anyway, I decided to do just that.
It was after midnight when I pulled in, and there were probably a dozen cars and RVs in the darker section of the parking lot. Having lived in a car, it's pretty easy to notice the signs of someone who is set up for permanent residence as opposed to an overnight stay. I got out of there early in the morning, but I estimate 10 of the 12 cars in the Walmart parking lot in Elko, Nevada were occupied by permanent residents.
Go to any parking lot (especially hospital parking lots) late at night and look for windshield covers on both the front and back windshields, curtains or rods for hanging clothes, ultra-portable bathrooms or cars full of clothes, and you'll realize the nomadic and/or homeless population is much larger than you previously supposed.