[Bells]

Even going by what you say, I don't really see how it makes him fake. If he cottoned on, I don't see why it would jeopardise his chances of winning or anything. It'd make him seem more appealing perhaps, because he managed to figure it out! His fans would have stuck by him either way.

And, as has been mentioned, maybe he did ask questions (about the housemates, that is), but they weren't shown. Alternatively, Pauline was meant to keep quite a low-profile, generally speaking, so the other housemates probably thought it better to drop anything that may affect their positions in the house. As for Carole, she was acting excessively suspicious, therefore I would imagine most housemates in there would have found the situation uncomfortable.

Also, Brian doesn't seem like the type to ask too many questions, does he? Every little detail probably didn't bother him, and he didn't think to ask why the diary room was different - he just accepted it. A lot of things go on in BB you cannot be sure about. Not to mention that he was probably too caught up in what was going on in his own BB UK, let alone in Australia! You can be a fan of something yet not be obsessed, after all.