I can't remember precisely how our secondary school computers worked, but they were definitely Windows XP and they definitely had some restrictions. However, apart from the obvious porn ones, I can't really remember what they were. At uni, it was still on Windows XP, but the restrictions were much less strict. Indeed, I don't actually think anything was physically blocked, but we were told that our IT use was under constant moderation. However, no one really seemed to care all that much, as they were too busy genuinely doing work! (The hours peeps spent in the library, oh my days.) At work, I haven't really tested out the restrictions, but it's a very similar situation to that of uni: people mostly are very busy and have work to do; the IT systems - when not screwing up - are mostly there to be helpful, so allow for more openness.