It's no conspiracy theory, that's exactly why Bandai Visual wouldn't license the Japanese audio for the BD. Otherwise, they shouldn't have been able to get it for the DVD. Code Geass, Gundam 00, and a number of other shows all suffer from the same problem because Bandai Visual is so worried about it. Meanwhile, Funimation doesn't have that problem with their BD releases because reverse importation is not as prominent as Bandai Visual thinks, and luckily, the companies Funi licenses from don't feel it's a big concern either. It all has to do with the idea that it COULD be imported back to Japan though, just as mikeggsm said. It's a pretty stupid decision too, since region-free DVD players are prominent now and so the DVDs could easily suffer from the same thing.