I enjoy pacelines and find them fun and valuable for training, but I do want to know that the other folks in the line know what they are doing. I ride in pacelines with people I know, but not with some stranger on the road because I don't know their skills. If I come up on someone, I'll either hang way back or pass them. If someone comes up on me, I'll usually ease up on my pace so that they will pass me.

Clinics are a good way to learn, but you also need to practice; one clinic won't do it. Clinics that provide follow-up practice sessions would be great, but I don't know if those are offered. Some clubs, even recreational ones, offer paceline skills rides. I think it's a valuable skill to have, but riders need to learn how to do it properly.