Plugin does not respect transitive dependency scopes properly

The Introduction to the Dependency Mechanism page has a handy table for deciding what to do with transitive dependencies and various scopes. The Maven ear plugin does not honor it in all cases.

Suppose I have a .jar file. Its name is b.jar. It declares a runtime dependency on a.jar.

Suppose now I have an .ear project. It declares a compile scope dependency on b.jar.

By the rules of the chart, a.jar should end up being a runtime dependency (transitively) of the .ear, and should be included in the lib directory. It is not.