Conversation heard as I got to the top of Stromlo, just before you hit Wedgetail and all the fast sections. Discussion had between two mothers of some family groups riding new shiny bikes, fairly decent Treks/Giants, all OEM specced:
Mother #1: When we're going down, if somebody faster catches up to us, we don't have to stop and let them pass, do we? (said with that touch of condescension towards people who want to ride fast and not a family-friendly cruising speed that best suited her preferences)
Mother #2: Some people do, but you don't have to.
I chose not to uphold the standard of etiquette that suggests those who summit first descend first.