I still reckon they could get round things. Depends on how much interest they take in computers. Maybe I'm more paranoid about them knowing more about computers because I knew more than my folks did. Perhaps I'm worrying over nothing.
But yeah, mates used to frequent my yard when we got the Internet, mainly because my connection was unmonitored and pretty much freely usable (this was in the era of dial up). So I'd say that kids will always be able to get access to the Internet via other means.
Based on my own experience of school, the machines there were easy to get round so perhaps they wouldn't even need to go to a friends house.