I have little to add to DrPete's excellent comments, but here goes. Let's face it, if no one is paying you to ride your bike, this is a hobby. By all means take it seriously and work hard, but this strikes me as making a mountain out of a molehill in order to feel better about yourself. If this were just about safety then yelling would be justified (and it frequently is), but physically removing someone from a paceline is certainly not the safest course of action. No, I think that yelling at newbs makes us feel like cycling is more than a hobby, and it makes us feel better for having disciplined the guy who would dare think that we are just a bunch of average guys out riding bicycles. By all means take it seriously, but that does not preclude making newbs feel welcomed to the sport and educating them so they don't have to get yelled at for not knowing something that they otherwise would have had no way of knowing. To me this is just courtesy and sympathy for the rider as a person, not just a body in a paceline. Treating someone who is trying to learn but lacks skill and knowledge (that you at one time also lacked) as if they are being intentionally reckless (most all yelling I see is for honest mistakes, but recklessness deserves an earfull) makes that rider a victim of your own power-trip. No egos means sometimes making sacrifices for people even when it is inconvenient, because that's how you hope others will treat you the next time you find yourself in his situation.