Carsten, I think the parents were 100% right this time and the schoolpeople were just as silly as one should have come to expect by now of schoolpeople. No crime was committed. In context it sounds like an offhand comment, not a credible accusation. But then again, ya never know. I remember a lot of side talk about a particular teacher of mine in high school. Nobody took it too, too seriously till the dude got busted peeping the girl's locker room through the girls' coach office one way glass window. Another reason to not even try to stifle such speech.
10 years ago, when my 8yo was fascinated with The Realm, I had sort of the same policy. The kids' machine was in our home office so we were always hanging around each other. I also just explained things to her and laid down some rules. Don't give out your real name, age or address. It's ok to lie sometimes. Look it up, there isn't even a X-tian commandment against it, honest to God. There's one about being a lying, dirty, rotten snitch (bearing false witness against one's neighbour) but not a peep about speaking untrue statements for good cause. But I didn't present this to her, or even think much of it, from a fear driven perspective. Instead, I saw it as an opportunity for her and I to learn some interesting truths, plus it would make a really fun entry for her home-schooling portfolio should it come into question at a later date. I wanted her to see for herself how ridiculously easy it is to fool a willing believer so that she would grasp the whole concept. That way I wouldn't have to waste precious time and energy making a plethora of specific rules or surveiling and enforcing them.
And you're right, guest. The net views censorship as damage and routes around it.