Forcing restaurants to post signs is enforceable.
Forcing employees to wash hands may or may not be.
I don’t think you can install cameras inside bathrooms. You may be able to move hand washing stations to the kitchen and have a procedure to make sure one washes his hands when leaving the bathroom.
Amazing times we live in. ;-)
Setting speed limits on th ehighways may or may not be enforceable either. Should they do away with those?