It's also a fire hazard. I'm sure they'd consider the worst-case scenario, and at present that's probably some serious arcing within a motor causing a fire. C

It's also a fire hazard. I'm sure they'd consider the worst-case scenario, and at present that's probably some serious arcing within a motor causing a fire. Cutting the track power (easily done by the driver) then makes that a fire that can be handled with water and/or foam. Smoke from large batteries would be very hazardous.