Does this make sense? ';Wash hands before lunch, no water necessary?';?

This is posted in my school and I don't think it is grammatically correct, someone please help me.Does this make sense? ';Wash hands before lunch, no water necessary?';?
I'm sure the intent of the poster is regarding choice and it is grammatically correct. ';Wash hands, no water necessary.'; Meaning, you can either wash your hands with soap/water or use an effective hand sanitizer that requires no water. The point is, it's just a reminder to wash your hands. It's the most effective way to lessen your chances of contracting the flu virus.Does this make sense? ';Wash hands before lunch, no water necessary?';?
The only way I could see it is if it is for hand sanitizer, but then it still isn't correct; because it should then say something like ';Use Hand Sanitizer'; or ';Sanitize Your Hands';. Are they adding soap as a flavor to your food? The soap just breaks the bonds between bacteria/dirt/microbials and your hands, water actually rinses them off your hands; you need both water and soap.
If you feel more comfortable using water to wash your hands, then I'm gonna take a gamble and say it's okay.
That doesn't make any sense to me. Maybe ask whoever put it up (possibly the school janitor) to tell you what that means.
Is it posted by a hand sanitizer? If not, then it doesn't make sense.
Why the question mark? Does it imply washing with an alcohol gel?