Actually doing what the question is asking, sure... that's "****ing stupid." Asking it ...is not. If that's what you're indeed referring to.

I'd be willing to bet more cyclists do things such as this more than you think. Matter of fact, I see it quite often. But, of course they're not going to admit in on this forum. If they did, some know-it-all, tactless holier-than-thou would call them "****ing stupid" or some other degrading asinine name.