Hair dryers have killed people too, which are much more likely to be found in a bathroom. It's why they all have GFCIs in their plugs. I've also heard tell of a girl who was electrocuted in the bath by her phone charger. The USB cord won't do it; the 5V USB puts out can't hurt you. But if the charging brick and 110V wall power cord you've plugged it into falls into the water with you you're gonna do the 15 amp dance.