Undo a branch

[Jerry Nairn]

Hi,
A colleague is writing a branch creation script which will make a branch
point tag name and a branch name based on the purpose of the branch
following a set of conventions, tag the branch point, and create the branch.
It all looks pretty good, but he asked me today about the best way to "undo"
a branch if the user decides he made a mistake. My answer was that this
shouldn't be something you do so carelessly that you would frequently want
to undo it, but that answer didn't satisfy him.
So my question is (are) what is the best way to undo a branch in an
automated way? What are the issues to look out for?
And actually, one of the things we discussed was the possibility of moving
the branch rather than removing it, if the branch point was on the wrong
revision.
So commands which might be used are:
cvs tag -d ...
cvs admin -o ...
cvs tag -F -b ...
cvs admin -Nnewname:oldname ...
We hope that this will only need to be done in situations where no new
revisions have been checked in on a branch, but any ideas about how to deal
with problems arising from such revisions are welcome.
Any ideas or advice will be greatly appreciated.
Thanks,
Jerry