At the HOPE conference last month, Stallman said he would on occasion borrow a stranger's smartphone should he be in a public place and need to make a phone call.
That's a common myth. Toilets have virtually no germs. I've seen so many studies that say "ice dispensers have more germs than a toilet", etc.
In a study done on germs on the areas of the body, the area around the nose came in first, the hands second, and the groin near the last. Germs don't come out of your butt.