One Pass Select Bias?
I didn't get the mileathon promotion invitation but my fiancee did, with the same mailing address. I'm Plat for 2007 already but she's only Gold and unlikely to make Plat next year. I assume they're trying to get her to fly more.
I wonder if you're already registered for OnePass Select they would disqualify you for Mileathon? Too much potential for double dipping on points.