Tampermonkey has actually blacklisted the URL of that updater. From the changelog @ http://tampermonkey.net/changelog.php:
@require Blacklist (sizzlemctwizzle updater domain is on sale, so avoid fraud by an evil domain buyer) -- You received this message because you are subscribed to the Google Groups "greasemonkey-users" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/greasemonkey-users?hl=en.
