As far as I see it, you can't become too rigid about average speed, etiquette, group riding style, the accepted way of riding up a hill or riding down it....because you just can't. CR's would become just too formalised.
If you get too hung up on average speed you are going to end up having an 18.25 mph group, 18.50 mph group, 18.75 etc etc. Average speed is just that, a bit slower on the hills, a bit faster on the descents, definitely a bit faster with an easterly on your backside.
Although generally of the same level of fitness, there are always going to be people in a group who are less fit or re-joining the group after a while off, and they are going to struggle more up the hills.
However we are always saying that people should move up when it's time in order to become faster cyclists. So this should be encouraged.
At the same time you will always get those who are faster dropping into a slower group, cos they don't like the look of the training group or because they are racing the next day, or on an easy week.
You can't stop them, because people have their own agendas, and one shouldn't have to justify moving down a group.
We are lucky that we have so many riders leading to a number of mph groups so that people can do this.
Etiquette is pretty much about knowing the highway code, knowing how to drive and knowing how to ride. Generally it's not too hard to pick up after a few sessions on the club run.
And as to riding up hills, well love em or hate em they are always going to split a group up. The best thing if you are faster is to make sure you are in the outside lane and wait for the stragglers at the other end. Having said that, it is very annoying to have to slow down just at the brow, and not good for the fitness, you just need to power on through...
I had a really good, if tough ride, in the 19s on Saturday, having been off the bike for 9 weeks, and just returned to it 3 weeks ago (thanks for waiting for me guys!) I wasn't on pace on the last couple of hills and slipped behind on the last section of thru and off. So I got dropped about 4 mins from the end.
But that is how it should be - I am over extending myself in order to get better. I shouldn't expect to be able to keep up in the first couple of weeks. And anyway, as everyone knows, I am only passing through the 19's on my way up to the training group
If people are mucking around on the hills, then tell them, if they are ripping your legs off at the front then tell them! If people are being daft on the road then tell them. But don't start laying down too many rules and regulations or the Club Run will become much less enjoyable and we will start losing members.