Dunno if the person you’re responding to is a lawyer, but you don’t need a law degree to know the statutes, or at least have a good working idea of what is likely to be illegal. In fact, as the judge will remind you right before passing sentence, ignorance of the law is not a defense. (That’s a real problem in some cases, but not so much for the garden-variety stuff like battery.)
Every jurisdiction is going to have a slightly different version on the books, but broadly speaking—as tons of internets will tell you—battery is “a device consisting of one or more electrochemical cells.” Oh, sorry. I mean, it’s “the use of force against another, resulting in harmful or offensive contact.” That’s from Wikipedia, but again, every criminal defense lawyer in the world has a page on their website for this.
I have no idea if prosecutors in shower-guy’s jurisdiction could ever be bothered to prosecute him for doing this, and for that matter (not necessarily having the benefit of all the evidence) I can’t say he’s guilty. But he’s definitely taking a chance here.
