After some discussion on the mailing list and related issues, it was decided that the slicing behavior of masked array where a view of the data and a copy of the mask were made was incorrect. Instead it was decided that both should be views. A proposal was made; however, this is a breaking change and it was discovered that the old behavior was documented in its current form. After some discussion, we have decided to deprecate the old behavior in favor of the new behavior. This issue is created to discuss where and how deprecation should be done and what warnings should be issued where to make this change clear.