Resolution: Not a bug
According to alexa.com, 4% of all moodle.org traffic goes to the demo site. I assume that others go there for the same reason I do: to try out new features.
I recently got burned by a serious discrepancy between the demo site and the latest stable release (see
MDLSITE-234). The problem was fixed quickly, but it left me wondering about the process by which demo.moodle.org is maintained, and what guarantees users have when using this site.
Suggestion: set up cron to put demo.moodle.org into maintenance mode and do a cvs update to the latest stable release at least once every 24h. Then advertise the site as the latest stable release with a 24h guarantee.
If this can't be done, the front page should warn users that the release may be different from latest stable release.