For many, many years AAA advised drivers not to travel in packs if at all possible saying, "You don't want to be involved in someone else's accident."  This advice is (obviously) directed at automobile drivers but surely applies as much or more to motorcyclists.  As many one-legged bikers can attest, if you don't have maneuvering room to avoid an accident, then you can only rely on dumb luck to save you.