Throwing water on cyclists

Is it normal for spectators to throw water on professional cyclists? During the final climb in today's Tour de France, I was shocked to see someone throwing a huge splash of water in Alaphillipe's face. Is this OK? Do the riders appreciate it on a long climb?

I put the video of it up on Youtube but unfortunately don't have enough posts to put a URL in. But if you do a Youtube search for "Spectators throws water on Alaphilippe in Tour de France" I imagine it'll come up.