$Name $ and branches

[David D. Hagood]

I'm a little confused by an aspect of CVS:

If I have a file that contains the $Name: $ keyword, and that file is 
checked out under a normal, non-branch tag FOO, the keyword will be 
expanded as $Name: FOO$. However, if the tag is a branch, the keyword 
won't be expanded.

Is there some logic behind this behavior? For some of what I am doing, 
I'd really like to have the $Name$ be replaced with the branch tag.