You mean like " always wear clean underwear, in case you need medical attention" ? " Don't talk with your mouth full" , " sit up straight " " eat everything on your plate "
Yeah, the underwear thing. But, doesn't everybody already do that, and not because a vague threat of hospitalization ?
"Don't eat so much before dinner, you'll ruin your appetite." (Hint, it's never happened in 50 years.).