Self-balancing scooters. Hoverboards. Whatever you want to call them, they're now a smash-hit in Britain. Companies are now scrambling to offer cheaper and sleeker versions in time for Christmas, but there's a problem: the majority are unsafe, according to Trading Standards. Officers have examined more than 17,000 "hoverboards" at sea ports, airports and postal hubs since October 15th. Of these, more than 15,000, or 88 percent, were deemed dangerous due to "a range of concerns" related to internal batteries and cut-off switches, chargers, plugs and cabling.