I was going through the "blacklisted user input" page on Physics, and I noticed that the standard intrinsic tag blacklist that stops users from entering the site name as a tag (e.g.
^physics$) was missing. Looking in to it, many older sites like Gaming, Cooking, Webmasters, Stats, TeX, Security don't have this blacklist. All new sites (regardless of the beta status) have it (try to submit a blank question with the site domain name as a tag and it'll give you an error).
Could the tag blacklist be enabled on all sites?