Comment There's a deeper problem (Score 2) 105
Some of the problems that have arisen here are not the fault of Microsoft or Google or other platforms because they are due to a deeper problem in setting times: times must be set with respect to a particular place - a time should be recorded as a pair of a time and a geographical anchor. Since calendars and other such problems generally do not do this, changes in the relationship between time zones can cause problems.
I participate in a seminar whose organizer is in Ann Arbor. It takes place at 2pm on Fridays. That's 11am for me in British Columbia, three hours behind. Suppose that a change takes place that makes the difference only two hours. The time will become 12pm for me. Their calendars should still be marked for 2pm, but mine should now be marked for 12pm. This is because the time is set by the organizer in Ann Arbor. Hers is the fixed point and mine has to adapt to it.
But suppose I were the organizer? Then the time would be set with respect to my time zone. If I set the time for 11am my time and the difference between time zones drops to two hours, I will keep my calendar unchanged but people in Ann Arbor will have to change their calendars to 1pm.
The point is that it matters which location is the reference point. Does the seminar take place at 11am referenced to Prince George or at 2pm referenced to Ann Arbor? In the current situation, with organizer in Ann Arbor, my calendar needs to indicate that it starts at 2pm Ann Arbor time. The time it would display to me would be computed using the appropriate offset from Ann Arbor time. Any calendar that records a fixed time, whether in local time or GMT will be wrong when time zone offsets change if the time is one whose reference point is not in my time zone. What is needed here is lazy evaluation.