Yes, like you wouldn't believe! Almost every game I play, as well as my own games, have a ton of hackers on the leaderboards.
We have a cheater's score on our Game Center leaderboard, and unfortunately we're not holding our breath in having it removed. Unfortunately, Apple does not give devs the options to manage their own leaderboards. Even worse, it's been over a month and Apple has not replied to our repeated requests to have this score removed.
I wouldn't spend any more than 10 mins trying to figure this crap out, if I were a hacker. Too much math for me.