Take any cybersecurity class and you'll want to burn your tech in a dumpster. In most cases it's security by obscurity from sheer numbers that hackers/sites don't give a crap about you alone.
Additionally, every site you have ever visited tracks your browser, IP, OS, location, and more. This AdBlock tracker is just observing that you have a plugin for ad blocking. That's the least intrusion that YouTube does.
In summary, there's no need to be paranoid, but only because everything that can be stolen or observed already has been.
It's always rude to not listen. So phones should not be allowed during class.
However, It's rude not to allow breaks, growth, emergencies, and the fact that they are in fact, kids. They should be allowed to socialize, enjoy youth, and understand hierarchy/respect. So to earn respect, you must respect first.
Let the kids have their phones/computers as that is the modern world we live in. They will have technology. Don't discourage it just because some people learned "you won't always have a calculator in your pocket". Well, now you do, so rather than ban it, teach them to USE IT!!! Just... properly.
Adapt the teaching, not the class.