Apparently some of the gaming press is starting to fall into that crap. A few sites, Gamespot most of all, are claiming Arkham Knight is the third game in the Arkham series. Um, what? Just because Arkham Origins was made by a different company, is a prequel and is apparently not as good as the first two* doesn't mean it's not part of the series. If the quality of the game is the problem, then that's the same as me saying only two Sonic games were made in the last decade, and as far as the prequel thing goes, you never heard anyone saying MGS4 was the third game in the series, right? (Granted, it's not the fourth either, but rather the sixth, but let's not nitpick about the MSX games, 'kay?)
*I haven't played it yet myself, but my brother tells me the only problem he had with it was that it was more of the same compared to Arkham City, which I have played. Now Arkham City is great, mind you, so I won't complain that loudly if that's really all there is. I've heard complaints about glitches and the story not being up to par, but as long as it's not an unplayable mess and the story doesn't make the game into a really unpleasant experience, I'm not going to rip my hair out there either.