(make-pathname :name "/root") - good/bad?

In LispWorks:
(make-pathname :name "root") ; --> #p"root"
(make-pathname :name "/root") ; --> #p"/root"

In CLISP (windows):
(make-pathname :name "root") ; --> #p"root"
(make-pathname :name "/root") ; --> error

The error is:
*** - MAKE-PATHNAME: illegal :NAME argument "/root"

If it makes a difference i don't have a directory called /root.

Which is the correct behaviour?
.