We've all seen signs encouraging people to wash their hands in restaurant restrooms. Many of us appreciate these prompts. We don't like to think about the people who are preparing our food disregarding this advice.
The idea of such a reminder hanging on the wall of a public school restroom doesn't seem like a bad idea. These are high-traffic areas, and illness spreads quickly. One sick kid leads to many sick kids, and they bring whatever they catch home with them. It seems like another good place to encourage hand washing.
What don't picture is a sign like the one here. It says, "Wash your HANDS and say your PRAYERS because Jesus and GERMS ARE EVERYWHERE." This would be fine in a church restroom, but we don't expect it in a public school. The Freedom From Religion Foundation (FFRF) intervened after a student attending a California public school found it there.
The good news is that the Victor Valley Union High School District promptly removed the sign. The bad news is that this required a letter from an FFRF attorney after a student complained. The sign would still be there if nobody in the school had the courage to come forward. This seems to be the case with most church-state violations, and that's disappointing. We all know how much pressure there is to keep quiet about them.