Oh, I'm aware they can. Heck, my son infiltrated ECPI's network through a printer. Had to write a paper on how he did it to avoid legal prosecution. We know kids are innovative and will do stuff. That doesn't negate the state's interest in making it more difficult for them to access this stuff.
Parents can fully exercise their responsibility at home, lock down internet access, not allow unsupervised phone or device usage, do everything the usual suspects claim they are supposed to do, and have all of that totally undermined when their kids go to school and administrative personnel who don't give a rat's flying patoot don't bother to police what the kids are watching on their tablets. If we all agree it's not a good thing for kids to be exposed to this, the state should take active steps to make it more difficult. I have to show ID to buy alcohol, I assume I would have to show it to buy an adult magazine in a store, why not show it to access pron online?