decided that the young woman would probably not appreciate the sarcasm, and took the MacBook off her so I could add in the county’s proxy server settings

I mean, the YouTube whatever, though calling that her fault is still douchey, but this is entirely on the author. If he’s logging someone on to the network and the network doesn’t work without a proxy configured, he’s the one who should know to set that up. That’s absolutely not normal end user behavior.