There have been some creepy clown reports in FL recently. I haven't heard of any of them threatening schools, but I may have missed it.
When my DD was a freshman a few years ago, there were two people in clown masks who were banging on dorm windows and freaking the kids out. The college did send out an alert to students. The rumor was that a group of guys were out tossing a football and spotted the clowns. They gave chase, caught one and roughed him up. There wasn't any actual proof that this happened, but there also weren't anymore clown reportings after that night.