So....after all this ... Is it an actual signal to the OP or the other three riders yet to pass? "watch your ass, passing on the left?"
I simply have no issues with roadies whatsoever. They really hate being passed on the road by a SS MTB with two inch knobbies though, THAT I can tell you. Most of der roadies avoid the core streets in lieu of the bike paths so I don't see them alot. To each his own.