Originally Posted by rollagain

I strongly second this.

Not too long ago I was on a ride and came over the crest of a hill to find two teenage girls riding side-by-side--headed the wrong way in my lane. I said, "You're on the wrong side of the road."

One of them said, "Uh, actually, no." At this point they were drifting across the road to avoid me because I was not yielding, and I replied, "Actually, yes. You're on a vehicle and you're required to obey vehicular traffic rules."

I didn't hear any more out of them, and I didn't care; I just hope they went home and googled it. Thing is, they should have known.