Storing all dates in UTC is a widely adopted convention, but it has a critical flaw for future-dated events: timezone rule changes (like DST adjustments or political timezone shifts) can silently corrupt scheduled times. For example, a cinema booking stored as UTC can display the wrong local time if the region's UTC offset changes between booking and event. The recommendation is to keep UTC for past timestamps but store local date-time with timezone context for future dates, using libraries like NodaTime or Joda-Time to handle this correctly.
