Some phones get stupid. Or should I say some phone MAKERS get stupid. My friend has an Audiovox SmartPhone, and it will NOT charge with anything but a real computer connection or THEIR charger. My Motorola charger won't do it, an iPod charger won't do it, a generic USB AC adapter won't do it. But there's some sort of encoding in that Audiovox charger that says "hey, this is ok, go ahead and charge!" Dumb!
(I keep an extra RAZR charger in my suitcase just so I have it whenever I travel.)