UML14 — UseCaseInstance badly defined

Summary: UseCaseInstance inherits from Instance, which inherits from
ModelElement.
Since a UseCaseInstance has no attributes and relationships defined, it
has
only those inherited, which are: name, the set of attribute slots and
the
link to a Classifier. Therefore, the statement "An explicitly described
UseCaseInstance is called a scenario" (Semantics pg. 91) has no
meaning,since
there is no way to describe a UseCaseInstance by means of anything else
than
its UseCase.

Considered and declined.