Re: Verification pending - all of a sudden

Our documentation provides more information which may help answer your
first question:
http://www.google.com/webmasters/sitemaps/docs/en/verify.html

"Periodically, we check to see if the verification file still exists on
your webserver. We do this to make sure you still own the site. If we
can't find this file when we recheck, we ask you to verify again."