The correct answer is departure date +2 so in your case Feb 28. Once you cross the dateline going West you lose a day. Coming back East bound you gain it back. So on the return, presuming you go east and not RTW, you'll arrive back the same day you left HKG. If you go West and travel continuously, you can make it back in Departure +1. No fun but doable.

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....airline economics: The only industry where the value of a perishable goes up as the best before date approaches....