[Terr_]

IMO the way to avoid insanity is explicit modeling, the pain comes from where different code was written with different beliefs about what the value "really means."

For example, if there's a lunchtime event in Bizarro São Paulo you record "Noon in Bizarro Brazil Time" or even ("Noon in whatever timezone that office building will exist in") because it really does depend on the rhythm of the city. In contrast, if it's an international video-conference, you might record it as a time in UTC or the timezone/city of the most-critical participants.

In both cases, users of the system should be able to see the "contract" along with the predicted moment in a probably-useful local representation. (I might not be in Bizarro São Paulo while I'm looking at the event, but I might know I'll be flying there later...)

If you're afraid a Bizarro-govt is going to do something weird at the last second and cause all sorts of customer complaints for missed events, you might code a system that keeps track of when predicted-times (in something safer like UTC or TAI) suddenly change for events in a way that might catch users by surprise, and then send out notices.

[scatters]

But also "whatever timezone that office building will exist in" may not actually be the same as the timezone that is actually used by the occupants of that office building. There are numerous communities which unofficially observe a different timezone to the one officially assigned to their locality.