Does everyone out there think Wikipedia is a pile of lies and useless
twaddle?

http://en.wikipedia.org/wiki/Usb

Scroll down to the Physical Appearance section.

VBUS is supposed to be loaded with no more than 0.5 amperes (0.9 for USB
3.0). What happens if you try to pull more than that (presumably) depends on
the design of the power supply feeding pins 1 and 4.