18. Newbies are not required to participate in a paceline and may stay at the back.
19. If you are struggling, don't expect the people behind you to stay behind you. Let the people behind pass to close the gap. One group I occasionally ride with has one older gentleman who has a tendency to struggle. He also doesn't like people to pass him - probably a pride thing. This guy is always creating a gap. When you do pass him and fill the gap, he always passes you (and several others) up at the next stop light.