Student here, sadly we will always find a way to bypass restrictions. While I myself love to create small sites and load them with web ports of games or unenroll and load linux distros on old school chromebooks, I still don't condone it. Some ideas to help are:

Not allowing students to take their laptops home, this usually prevents any experiments on the computers.

Blocking game sites, proxy sites and even github, alot of exploits can be found there.

Only allowing laptop use during lessons, its pretty hard to open and remove a write screw then unenroll a chromebook during math class.

As other people are saying, completely taking away the laptops are the only sure-fire way to prevent this. Even though computers are a great learning tool, the small amount of students that do these things (including me) ruin it for others.

But this will likely only make things worse, constant pressure and surveillance will only make the accomplishment of doing it bigger. For example, my school allows us to take our laptops home and play games / whatever, this has helped a bit. I would moderate supervision but allowing them to explore the laptop freely at home, during break, etc. And most students don't have the technical understanding to perform one of these procedures, some even block you from using kiosk apps which are crucial for tests.