You know it's a Big Brother twist when the problems it could cause outnumber the interest it might stir up. Oh, and it has to be stupid. (Not 'could be'. 'Has to be'. So says that greatest of authorities, Previous Experience.) For this one, the issues are many, myriad, and dumb, starting with:Early departure Do we get a replacement? Are the hamsters ever told what happened, or do the producers keep making things go wrong just to play with their heads?
Jury presence Should the saboteur reach the five-week goal, all but the strangest jury configurations would give them a place there. Does the saboteur get to be on the jury? Does s/he control hir own vote?
Limited saboteur materials, too much observation, stupid suggestions CBS is not giving their spy access to much as far as helpful items go, just getting at them is a problem, and there's only so many blackouts you can have. House population and location spread means there's always a strong chance of being caught. Filtering out the Twitter suggestions will give them only the most idiotic low-rent options to execute -- and, given Endemol, the ones with the highest chance of being caught. They don't want to pay hir...
Staying in the house beyond deadline Since the saboteur's goal is to reach the halfway point, what happens if s/he gets there -- and remains in the cage? Can't play for the top prize, sure, but that just makes hir the perfect F2 partner. Or how about bringing hir along, s/he wins the jury vote, and Endemol gets to say 'Sorry, but the rules say that one can't win: no prize this year.' (Arguably their ideal finale.)
You know it's a BB twist when it's stupid.
When they're still openly proud of it, you know it was Grodner's idea.