Let the hive mind of Engadget get that for you.
"We need a digital camera that can be switched on and fire off that first shot fast. It's not a commonly tracked statistic on any review site, and nobody seems to have this information for every camera. We were hoping other readers could inform us as to what small digital cameras can fire off their first pics in under a second (ideally under half a second). It needs to be small, but mostly, just really quick in operation. Thanks!"
IIRC the USB spec is max. 500mA current draw on the 5V supply pin. So total power a USB deviceis "supposed" to draw is 2.5 W.
With this device drawign ~4.8W of power while burning I can't see too many laptops or USB ports supporting it (most have current limiters).