Let's see, I guess US Airways feels it didn't upset enough loyal customers with its recently rescinded "no preferred miles for discount fares" policy. Now it's trying to alienate many of its best customers by revoking bonus offerings after persuading them to get out more and fly on particular routes.
I agree with others here that, instead of going after customers, US should clean up its obviously messy IT operations. Fixing its IT procedures will make a bigger difference in improving profitability than jilting customers. And if it does go after customers, there's little reason to believe that US will be able to accurately identify "unearned" bonuses. Inevitably, there will be lots of confused and angry people who will feel cheated by US because they responded to targeted promos only to find they have been de-qualified. This all sounds like the makings of a marketing and PR debacle.
US should consider the recent wave of preferred miles promotions as a gracious and generous way to reward and welcome new elite customers into the excellent DM program. US should turn this into an opportunity to have the elites fly and pay more to keep their status. By blaming customers, US would only provide more evidence that it lacks the managerial skills to return to solvency.