In California certain constitutional rights are forfeited the minute you step on school campus. Mainly the ones you already mentioned.
It's the school's job to keep you safe. That's been deemed important enough for you to sacrifice those rights. I'm against things like the Patriot Act, but I really don't see the problem here. What do you have in your locker and/or car that you don't want to see? If you don't have anything allowed, what's the problem?
Now what does get me pretty hacked is when people get expelled for things like having been "caught" with a pocketknife, multi-tool, etc in their cars, on school campus. Things like that are an example of not using common sense to interpret rules.
And on the network issue, you're using their network, it's a private network, and they determine the rules. Just like you have freedom of speech, but you can't just start cursing everyone out here on ChiefDelphi, because it's ran by a group of individuals that make their own rules. Rules which very well may impair your freedom of speech, but that's just too bad.
Also, this is almost backwards thinking, but that raid could have had a beneficial effect--Who in their right mind is going to bring a gun or weapon on campus after they just had the SWAT team storm the school and hold them at gunpoint?
Maybe if people actually respected(some) laws and rules, we wouldn't even be having this discussion
$0.02