Well I am not totally convinced that there isn't going to be 14 houseguests this season. I find it very difficult to think that someone got cold feet last minute and they didn't replace the person. They have so many back ups in place for this type of incident. This isn't their first rodeo, and besides this has happened in the past on another season I believe it was 8...where they had to have someone fill in last minute because someone's info got leaked out or could have been leaked out....but basically someone they had anticipated being apart of the show wasn't and someone else got the slot... They have the show planned out how they want it to go and I just don't buy that when they could replace someone easily before the show starts they choose not to. Doesn't add up!
With that being said I am leaning towards Andrew being the saboteur. I would think you would at least need someone with qualities much like Eric season 8 had to pull it off well.