The AP has walked back that article -- headline now reads "Cellphone use heavy, but still operating in Boston". I don't see any note of a retraction or correcti

The AP has walked back that article -- headline now reads "Cellphone use heavy, but still operating in Boston". I don't see any note of a retraction or correction. Anyone know of any good resources to explain when news organizations find it ethical to transparently change articles like this, and when it isn't?