“I wonder if you can run 2 or 3 Raspberry Pis from it if you don’t need it for connecting extra USB accessories to. Based on the power of the power supply it should be, in which case could provide a good way to power multiple Raspberry Pis in a classroom (although I don’t suppose that is officially supported).”
…which was far too irresistable a challenge and had to be tried out immediately. I didn’t have a dry run. What you see in the video is the first time I tried this out. I didn’t know if it would work or not, but I expected that it would. The video is a bit “quick and dirty”…
I connected four Raspberry Pis to the hub. Two had Edimax wifi dongles, one was my RaspiCamcorder and the fourth was my weather station Pi (on ethernet) with LCD attached. So for the test, I fired up the weather station, started recording on the RasPiCamcorder and ran an LEDs demo on Pi 3. The yellow Toxic Pibow Pi was idling. It was just a silly stress test, but it passed without a hitch.
I don’t necessarily recommend you use the PiHub for this, as it’s a bit of a waste of its USB downstream capabilities. But it’s nice to know that you could if you wanted to.