[quote=Also, it's beyond me how a new process using real magnesium can produce a product that stays shiny - magnesium seems to be like rust - it's alive and never rests.[/QUOTE]
It wouldn't be the process, but the formulation of the alloy. Magnesium is one of the most "active" metals there is. Kind of like a cheap hooker, it wants to couple with almost everything around it!
Aluminum actually protects itself by corroding. The resulting oxide (known as rust on iron) seals the underlying metal against oxygen in the air and protects it from further corrosion. I believe the process is similar with Mg. So when you polish off the oxide you're actually removing the protective coating and exposing the metal to additional corrosion. Better to seal it and skip the polishing (at least with Al).