As far as the unlimited voting goes, while I think it does seem inherently unfair to let teenie boppers vote nonstop for someone to get further in AI, I don't think the producers would look at it this way. AI is a huge marketing focus group. The entire premise behind AI is to "discover" the person that can be shaped into a "music star" and sell lots and lots of records and lots of tickets and make lots of money for the producers. Well, who spends their money on CDs, posters, and concert tickets but teenagers!!!!? So the fact that teenagers would propel the candidate to the top is only validating the premise of the show: the one who gets the most votes wins. Votes = Money when the contest is over.
A little cynical, but I still love the show. But that's the way it is. And I just take comfort in the fact that my faves: Taylor, Chris, Katharine will still probably get recording contracts. They just won't have the "AI Machine" behind them.