You might be right. I was trying to disentangle "time" from "calendar" by showing that just because someone doesn't know anything about calendars doesn't mean you can't coordinate with them to meet at a future point in time, and THEREFORE you should indeed use an offset to represent points in time and local timezone to represent points in a calendar as I originally claimed.

In retrospective I wish I'd chosen a less fantastical example, because of course people are gonna get distracted. "Aliens" was not the point. But now I can't be bothered anymore, losing interest fast.