[O] Leading headline of a subtree tag export

[Scott Randby]

I had a file with the following structure:

#+OPTIONS: tags:nil
* Grades
** Student :studenttag:
:PROPERTIES:
:EXPORT_FILE_NAME: Exported-Grades/studenttag
:END:
*** Totals :totals:
    Content

Whenever I exported the entire file, no tags were exported (what I
want). However, whenever I exported the Student subtree, the tag for
that subtree was exported (not what I want) but the tag for the Totals
subtree was not exported (what I want). Then I tried the following:

#+OPTIONS: tags:nil
* Grades
** Student :studenttag:
:PROPERTIES:
:EXPORT_FILE_NAME: Exported-Grades/studenttag
:EXPORT_OPTIONS: tags:nil
:END:
*** Totals :totals:
    Content

The tag for the Student subtree is still exported when I export the
Student subtree. How do I prevent this tag from being exported when I
export the subtree?

Scott Randby