We've had this problem locally and we're a very rural area. Seems to be a nationwide phenomenon.
Curious at to what's spawning it - takes some time and money to go dress up like a clown - and then to go menacing people? How are people that stupid especially considering how many are armed?
It is a viral internet joke, kind of like planking. At that, after a few people did it and the media freaked, that just caused more to do it.
What is more disturbing though is how violent people are getting towards some of these.
At a local university, one kid was just walking around his dorm with a clown mask on, and the University called the police. He wasn't being threatening or anything, just wearing a creepy clown mask.
As a reminder, this is October.