There's a difference between yellow jackets and bars/stripes. I don't wear one in the cockpit -and have got out forgetting to put one on. I once even tried to go out to get another can of EN228 from the car without one. I almost said "Sorry Mummy" to the rather attractive brunette who gave me a row like I hadn't had since pre- teenage. For those of us using commercial airfields they are essential. And outside they don't distinguish us from Court Ordered Community Service Litter Pickers. Except my one is oil stained, and there's are pristine clean.