Well that does cause a problem when it doesn't differ between manga that just haven't been scanlated yet and those that can't be uplodaded, as someone could assume a series is one of the former and upload a chapter that he shouldn't.
That just really doesn't make sense though. You're assuming (in that scenario) that whoever (scan group/contributor) wouldn't just go to the page in question and see what the deal was....i.e just no chapters or had content actually removed/been banned for whatever reason. The page itself normally has notations regarding any problems, and even if it doesn't it's not really that difficult to figure out if there is a problem with adding content.
The main reason for "tags" is compiling lists.........and as Daktyl says, the "no chapters" tag accomplishes what should be seen as the biggest benefit to both the site and the readers, that being the exclusion of titles that don't have content from compiled search results. As they stated, the why it doesn't have content really makes no difference (to someone looking for something to read).
After that....well, it's really just idle curiosity, isn't it? What real benefit does either the site or the readers get from adding specific tags like this one suggests? What real purpose would it serve to either the site or the readers who are just looking for something to read and want to avoid wasting any time getting titles that don't have content in their search results?
I'm not trying to shout down suggestions.....what the OP suggests doesn't exist and there's not a thing wrong with bringing it up. I'm just weighing in that, on this particular suggestion, I don't think there's a real benefit to anyone from it. Just take a look at Manga/Baka Updates....trying to make a tag for every little thing is how you end up with 3,000+ tags and an unbelievable glut of useless information.