http://www.wsmr.army.mil/PDF/motorcy...tyhandbook.PDF
That handbook is for the army and just an example. They have their own regulations which require a lot more protection than legally required in states (motorcycle gloves, bright/reflective garments, etc). There are also inspections of the bike.
When I visited Cazper in Camp Pendleton, he did warn me they'll ask for my MSF card upon entering the base. I was pulled over and told that I couldn't wear earphones either. They are protecting their investment in their people.