it's true that no one wants to be interrupted by a newbie when they're in the middle of a focused training routine, and an inexperienced rider joining a fast double paceline is just flat-out dangerous to the other riders, but i've found that the serious riders on expensive, tuned, custom bikes who have refined training and racing agendas are often the most outgoing riders out there.
there's much to discuss, much to share, and it seems that everyone i ride with has questions about the other guys gear or training routines.