the so-called Chromebook Challenge includes students sticking things into Chromebook ports to short-circuit the system.

I am rather surprised that works. I thought any modern device would have overload protection in place. I think I even remember accidentally tripping it on some device, but it would just reset after reboot.
I also tried to see the max output current of my previous phone this way. Load it up till the protection trips. Result: Stable up to 2.1A, tripped at 2.5A.

Oh, yeah. A Xiaomi phone charger I have also shuts down if I either overload it or immediately load it near max rating rather than gradually increase the load.