Our club has a "safety officer" that will occasionally get involved with situations like this.

Normally if someone is flying by themselves, they can do whatever they want.

However once someone else takes off, everyone must fall into an established pattern.

We all try to look out for each other, and keep out of each others way. Everyone values this.

We get the occasional person who doesn't follow in.

Everyone else starts shouting "the pattern is right to left" or "the pattern is left to right" and the experienced members take great pains to declare their takeoffs and landings to hopefully demonstate HOW these erratic flyers are expected to behave.

However if the hints are not taken, the safety officer is alerted, and our members are somewhat vocal about enforcing some basic good practices.

Usually it only rarely gets as far as the last steps, as leadership by example tends to work very well, especially when everyone else is doing it.