The path_persist class, as implemented, will override
GET values coming to a page.
This can happen, for example, if you send a newsletter
off to a Perl script that sends the newsletter via a
socket and then returns to a result page. (we wouldn't
know of any applications doing that, now, would we??)
Since the path_persist stuff can't be passed to the
Perl script, the GET values are overriden due to the
logic in the initialize() method (I think) which seems
to ressurect and force all the vars to be the old ones
if the persist stuff hasn't been passed.