Ive seen that tactic used in San jose so that two cars can race ahead with mostly clear road (illegal of course) ive also seen that same tactic used on 395 north right were that 50 mph sign is that tell every one that they need to slow down and all that and into the south side of reno. in fact i remember it was a chick in a minnie van and some dude in a green tacoma 4wd. i thought about doing the pass on the shoulder and then get in front and put on my brakes to separate them but honestly didnt do it cause i didnt want to cause an accident from the chain reaction it would cause with the hundred plus cars behind them! beside theres signs that say Slow Traffic Keep Right.
In my opinion if theres anyone behind you thats less then two car lengths from you then your slow traffic even if your doing a 100mph!!