I remember in the early days you could fairly easily fry a USB port on your computer if you plugged in the wrong thing. I think they are far more tolerant these days, though the recent USB Killer doodad that's been going around shows that extreme abuse can still break things.
It is one thing for things not to work if you plug them in, but when shit gets broken by doing so then that's just inexcusable.
I don't think i have ever seen a USB port get permanently fried from having a device draw too much. I have however managed to fry a cheap thumbdrive by reversing the connector on the motherboard...
Meh, that problem is still there. On top of how Apple has their own take on signaling that the charger is "dumb"...