A young project manager in my team came off a quad bike in Morrocco in September, usual thing, never been on one before, out with a guide, no safety training etc etc (sound familiar?). She is still of work with her jaw pinned back together, severe burns to her face (the bike landed on her, and yes, she was wearing a helmet) a fractured arm, hip, collarbone etc, internal injuries. She is extremely distressed and not seeing visitors anymore because of the scarring etc. these things are unstable and absolutely deadly in all but the safest of hands. Ban 'em I say - unless the riders have a bike licence.