> I guess that the only viable approach is to assume that it works based on what we know today, and to treat future changes as unpredictable events No, the onl

> I guess that the only viable approach is to assume that it works based on what we know today, and to treat future changes as unpredictable events No, the only way is to store the user's intent, and recalculate based on that intent when needed. When the user schedules a meeting for 2PM while being in Glasgow, the meeting should stay at 2PM Glasgow time, even in a hypothetical world where Scotland achieves independence from the UK and they get different ideas whether to do daylight saving or not. The problem is determining what the user's intent actually is; if they set a reminder for 5PM while in NY, do they want it to be 5PM NY time in whatever timezone they're currently in (because their favorite football team plays at 5PM every week), or do they want it to be at 5PM in their current timezone (because they need to take their medicine at 5PM, whatever that currently means)?