Wow. I've deployed a bunch of Leviton USB outlets (http://www.amazon.com/Leviton-T5632-W-Charger-Resistant-Receptacle/dp/B00J3PMU4C/) because i really dislike having these stupid wall warts everywhere. This sort of begs the question of whether the Leviton boxes any smarter about shorted connections. If nothing else, the outlet is properly grounded, and hopefully when they designed the USB side of the circuit they took advantage of having a proper ground wire nearby. They were at least smart enough to support 2A charging on both Apple and everything else.

(That said, there's no externally visible fuse. Hmm.)