UMLR — UML 2.0 Super/Use Cases/Subject of a Use Case

Section 16.3.2 allows "classifiers in general to own use cases". Section 16.3.6 however states that the "subject of a use case could be (...) any other element that may have behavior". These elements are called "BehavioredClassifier" by Section 13 and are a specialization of Classifier.
Please clarify the consequences of these statements:

• may all Classifiers be owners of UseCases, but only BehavioredClassifiers be the subject of a UseCase?
• what is the semantics of Non-BehavioredClassifiers, e.g. an Interaction or OpaqueBehavior, owning a UseCase or being a subject of it? A UseCase "represents a declaration of an offered behavior" (16.3.6), so how can Non-BehavioredClassifiers ever offer a behavior?