What is supposed to happen when you take a flight at 4:10pm on 8/7/2011 and land before 4:10pm on 8/7/2011 (local time)? Do you get the alarm twice?
Though if you lived close to a time zone border it could be a problem. There are towns straddling the Queensland-New South Wales border in Australia. There is a one hour time difference between the states for half of the year (NSW does daylight saving, QLD does not). I've always wondered how local businesses deal with that.
And I've even lost a birthday flying back in the other direction. Great scheduling, that.
Or use a fast plane going west (Concorde used to take ~3h for London to NYC, and NYC is on UTC-5, so passengers on Concorde would arrive "2h before they left").