Zoe Doidge
Basically a Goddess
I taught kids aged 13 or so who had obviously watched porn. When they had no idea what was acceptable in a school setting, there were some difficult and unexpected moments. In a public school, most parents expect a minimum decorum level. I agree with the ban, because there are certain parents who won't or can't enforce it.
Think about it this way, you've got parents who know what they're doing, parents who aren't even aware there's a problem and most parents I would think are somewhere in-between. Which is to say they're concerned about it but they not technically minded enough to know what to do about it.
Suddenly the government announces they've blocked all porn by default. Yay! Parents no longer have to worry.
But in reality this is just sweeping it under the carpet. Filtering systems weren't really a challenge when I was in school (so we're talking 10-15 years ago), everyone quickly discovered how to bypass them because we wanted access to email and chat sites etc. The concept is exactly the same with a government level filter. Most parents will think they're safe (and therefore don't have to actually do anything), while the teenagers will just bypass the filter and access what they like.
It just ends up providing lazy parents with a false sense of security, if anything, it's just going to make matters worse.