A few months ago Victoria Azarenka did exactly the same thing at a tournament. Show up, win one match and withdraw so she wouldn't get a 0 pointer.
With the Olympics they should've been more leniant with the mandatory tournaments this year.
But he was only defending like 90 points or something. I think he said earlier it was his only chance to meet up with his coach before USO so I think that was probably his main reason.