I hope it's not the case, but I have to admit that my suspicions have also been raised that these are, in fact, doctored Pianoteq samples. I had noticed from early on that some of the samples had an oddly synthetic twang to them (particularly the Bechstein) but it's easy to dismiss these types of concerns when your frame of reference is with other free amateur pianos where the general quality level is, frankly, pretty low.
In any case, what always struck me as most exceptional about these instruments was their consistency, low noise floor, and playability, which are extremely atypical for free amateur pianos. However, if they are simply recycled Pianoteq, it would go a long way to explaining this, as these are all areas where Pianoteq excels.
Anyway, I'm sure the truth will come out eventually, and I'm curious to see where it all goes.