[Bombardier]

I really do hope BB isn't doing anything untoward.

One thought I had is that, as we all know, the tenth anniversary celebration will involve a "twist." It could be that they want to keep certain housemates in until that twist takes place (e.g. they don't want Lisa to go until she's gotten a good pasting by another loudmouth who they're putting in... or they don't want Sophie to go until they put in a hunky black dude).