Quote from OP
"It's understandable that someone being taught new techniques or skills is going to want to try those out, Grifter pointed out, and often the quickest way to sort this out is to locate the source – sometimes in a training session right there and then – and pop your head around the door and tell them to knock it off, please."
Ah, yes, the point in the academic year when you (as duty rota manager) are asked to explain to a group of IT students that the College network is both reasonably secure and, more importantly, closely monitored. And could they knock it off.
Icon: to all involved, beer or bubble tea as appropriate.