This sounds very familiar. In my final year at school I was given privileges to 'monitor' the school's computer lab over lunchtimes. What that amounted to was really just reminding the other students to save and leave before the afternoon lessons started.

I thought better and that I could automate this task by writing a small background task in VB (4 or 6, I can't remember which year/version) which would listen for commands on UDP.

One such command would initiate an immediate shutdown. Without prompting the user to save open documents.

Only once I issued that command to the entire lab.

I didn't take long for everyone to find out who did it since my own machine was still logged in and working.

The next day I removed the process from the machines lest I get myself in any real trouble.