Good point.
I was remembering the Ford promotion you earlier linked to (thanks again), which gave away points, and briefly went offline so it could re-rig its own process so anyone who won could only be awarded one set of points.
But their revision was to link the entry to the Windows Live login? Or was it just email? All I remember is one guy here won 4200 MS Points, and I got 200 before "the magic died."