"Applying a reverse polarity voltage, or a voltage exceeding the maximum rated working voltage of as little as 1 or 1.5 volts, can destroy the dielectric and thus the capacitor. The failure of electrolytic capacitors can be hazardous, resulting in an explosion or fire."
Even a small one could take somebody's eye out if they happened to be close to it when it failed and not wearing eye protection.
When I was first playing around with electronics as a kid using kits and individual components purchased from Radio Shack I once put an LED directly across the terminals of a lantern battery.
The LED exploded sending little bits of plastic flying off at high speed. They all missed me, but if I had been in a little different position when hooking up that LED my lesson in the importance of using current limiting resistors with LEDs could have been punctuated by a serious eye injury.
I'd say that a paragraph when each component is introduced covering what bad things that component can do if you exceed its voltage, current, or power limits would be a good idea even if the course is only dealing with low power systems.