[leafnode-list] Should touch_newsgroup touch the first or last article in the group?

[Adam Funk]

I think that `touch_newsgroup alt.foo.bar` updates the access time of
the first article in /var/spool/news/alt/foo/bar/ and that this keeps
texpire from deleting old articles in that directory (unless the -f
option is added).

Is this correct?  

Would it be better to touch the last article in the directory instead?