Or their wife's safety. I love how pretty my wife is, and if she was disfigured in a crash, I would blame myself. Mine got the full magilla when she said she'd be ok to ride along - boots, helmet, gloves, pants and jacket. Funny, it does make her butt look fat because they haven't quite yet figured out how to make gear that fits women.
On the shorts issue - I prefer to wear gym shorts and t-shirts under the Motoport on a hot day. But when you slide a ways, the heat generated by the friction of your slide has to go somewhere. Guess where it transfers? Yep -your exposed skin. I wore bandages for about two weeks, but now I usually am wearing some of the very thin breathable cotton undershirts and thin cotton pants (either LD Ryder style or REI thin material cargo pants. No less hotter, but at least the friction burn can be easily prevented.
Good for you, Uncle H, giving your Harley pals grief. I still bug Mikey at the tavern, who actually has crashed his cruiser and still wears his beanie cap, but it won't change his mind.
I do a lot of activities with Steve McQueen's kid Chad. When he's out on the track, or even just in the canyons, no excuses. If you show up without proper gear, and if you ride like an ******, you're done - dis-invited and not welcome. He's hit the wall at 175 mph, and it was the gear that saved him from death (plus some very skilled doctors). It's a driver's and rider's code and if you feel otherwise, you're welcome to ride by yourself. It's highly effective at changing group behavior.