But they did have a reason: quite a few airlines have developed a bad habit of making big negative changes to their programs with little or no advance warning. The results is what we saw during the last 24 hours: a frequent flyer community that panics at the slightest hint a major devaluation may be coming.

I suspect the rumors of an impending BA devaluation would not have been so widely circulated if not for the airlines' own past actions.