You are correct. My dog has such an account.
Seriously, it does take time and active attention to home-police kids' use of the internet no matter what type of school attended, including home school. Time, attention and knowledge -yours and theirs- are the keys.
Analogy: gun control. If your kids aren't exposed to guns and learn respect, how to be safe around them, then they will grow up to be afraid of them and against all gun ownership - by habit and your example.
Advocates of delegating internet policing duties need to understand that only knowledge, attention and time spent ONLINE side by side with your kids will achieve your goals.
Your dog has a myspace account? If he or she is the friendly type, my cat might want to add someone to her friends list. lol. Yes, my kids insisted I make a myspace account for the cat. I felt so white and nerdy.