It might need a little more work, "If you ride this in the rain you could potentially kill yourself."
dude sounded stoned in that vid
Having 50,000 volts nestled just below ones privates might explain it, or that is the toxic effect of Beijing air, or he hasn't spoken English in a while, or... Never mind the rain. A crash with those big capacitors would be a shocking and hair raising experience. He also rides like he is stoned. Worrying about air quality when you might electrocute yourself in a sudden pop-up shower or a puddle splash is also good evidence of recreational drug use. Simpler to get a nice big Li-ion battery and power the self contained power filter masks available. A lot less chance of electrocution.