We have a Wednesday night ride that's not a club ride, but more of a show n' go ride. Even though there's a signup online most people don't bother with it since its a longstanding ride. There used to be 3 levels, (A,B,C) and a somewhat equal distribution in each group. Over the years, the A group has gotten much bigger (30-40) and very few (5+) in the other two groups. The local racers love this ride since its a hard training ride. There's no leader with the A group, but there are a few that can demand the attention of the group if a point needs to be made. We usually get there about an hour early and do a 20 mile warmup before the actual ride. This is double paceline tempo pace and nice for conversation. Then we regroup and head back for the real ride which often picks up quickly since most are already warmed up. If you didn't come early, you're in for some hard efforts before the legs have a chance to warm up. Some riders do get yelled at during the ride for doing bonehead moves. The A ride is not a steady pace, but a series of attacks and surges that ramps up the pace. There's a sprint zone in the middle after a bridge and one at the end that can get sketchy, so I'm careful at that point.
The B and C groups ride in a steady paceline and not sure if there's a leader since I don't ride with them.
The weekend group rides are very different depending on the group. Some groups have a leader, the club ride doesn't. It depends on the route whether we'll wait for someone if they get dropped. If we notice someone struggling to hang on we might adjust the pace to allow them to catch back on, but if they're seriously struggling we'll likely move on. We won't drop someone that's unfamiliar with the route, but we also don't like seriously adjusting the ride to accommodate. Most are well seasoned to just ride in solo if needed, but more often, one or two will drop back to ride back with them. A friend and I recently turned around to go pick up a rider we knew was struggling and she appreciated it. Even though a ride description may say its a no drop ride, be prepared to get dropped if you aren't able to keep the advertised pace. Always good to discuss this before the ride if its a concern.