I wouldn't count on that. 'America' gave Corey a Care Package and Grodscunt was dripping for Nicole, she'd probably have rigged it.
What you just described is jury management though, which is half of the game. If you can't convince (at minimum) four or five people you've lived with for three months to award you $500k/$1m you don't deserve to win. That is the game. Sure, I'm not happy with the outcome of every jury vote in history, but it is what it is and ultimately the blame (mostly) lies at the hands of the person I wanted to win - and I can deal with that, in much the same way I can if they're voted out.
But with public voting? It's on a whim, certainly in the UK the public's taste is appalling - and I know this'll be contentious but I'd go as far as to say BBUS has far better winners overall than we do. The biggest problem though isn't any of this, it's the fact that it makes no sense to spend ten weeks playing an isolated social game among your peers and then to have the winner determined by a popular vote
you could do all the work and then lose for something trivial like not being attractive, not playing up to the cameras all season, etc etc. Pick a format and stick to it