> future zoned datetime carry outright uncertainty as to their actual location on the timeline (as the zone’s offset can be updated at any point and any number of times until the event has elapsed)
I wondered if it would be worth applying a (optional?) version to a timezone when stored, so you could distinguish between "whenever it is this time in Perth" vs "when I currently think this time will be in Perth, though if Perth changes its mind on how it offsets time, I want to keep what time I currently think that will be".
But you're right, that doesn't really add anything over storing it as UTC.