I taught marketing classes at a university and had a whole collection of dumb product warnings that I used in class lectures. Since retiring I've not visited those in some time but a couple that I remember was the warning on a sun shield that you use on the windshield to keep the sun out said "do not drive with sun shield in place" like they think some idiot is going to drive with a piece of cardboard covering the windshield! Another one was for a hot brush used to straighten hair. It said "do not use while sleeping". Tell me, how do you do that anyway! Wish I could think of more because we all need a good laugh today. Maybe others can add to this.