Yes I think the surrounding of a roll cage and having harnesses, give some people the false sense of security. What they don't think of too, is a helmet won't only protect your dome in a crash but it protects you from roost from other riders and other trail obstacles. Can't tell ya how many times surprise downed trees and limbs at head height have popped up out of nowhere.Yes good thing no one was hurt. As far as side by sides and helmets, I think many think they are protected because they are "strapped" in. They may not be thrown and or stay in the same position but that won't stop a large boulder from invading the cab space while the vehicle is rolling or coming to rest. Rock versus human tissue.....Rock usually wins. Even more dangerous is a quad rider without a helmet but I think it is more common with the side by sides due to a false sense of security.
"Dress for the crash not for the ride"
I hear that all the time when riding my Harley. It honestly makes me cringe when I see people riding in wife beater, shorts and flip flops. The good makings of quick road pizza.....Dress for the crash not the ride