Are Orbitwheels as incredibly dangerous as they look?

I was on a plane the other day and saw OrbitWheels in the Sky Mall catalog for about $100. Something did not add up.
I have more than basic understanding of the Laws of Physics and it is readily apparent to me that since these wheels are not tethered in any way, they have the potential to separate, spreading the user like a wishbone. They may also twist independently in any of the axes causing the rider to either do a face plant, leaving teeth in the asphalt, or performing a skull bounce on the pavement. Maybe it’s just me, but neither of those options sound like fun. Am I missing something?
Does anyone here own a pair of these? Are they as dangerous as they look? Would anyone want them?
I’ve got a great idea that will save you money. Send me $50, a half price offer!, and I will simply smack you with a bat making sure to avoid the face. You will be much better off.