A boy in elementary school in Texas was suspended for playing make believe at school. He had a ring, and was pretending it was the One Ring from the Lord of the Rings with other children. When he told another child that the ring could make him invisible, the school said he was threatening the child and suspended him.
While I can't speak for the other two incidents of this kid being suspended in just the past 6 months (one time he was suspended for bringing a Book of Knowledge to school that had illustrations of pregnancy..considering he has a little sister, I think he already knows all about pregnnacy) I can say that no school should be suspending a child for playing make believe! What kid doesn't pretend to be a character from their favorite movies or shows? It's so totally normal!
And if it was a "threat" to tell another child he could "disappear" when all the ring does (if it was real....) is make you invisible, you're not disappearing at all! Now, I might say that maybe the child was scaring other children with it or something, but considering the school refuses to comment, how can we know'?
Either way, you should just be safe and leave your rings at home. Lest you be suspended, too.