Well, it was only a matter of time.
I really have no idea about the file system on the Xbox 360. However, I do know that you can save files to a USB drive, and then take that USB drive and plug it into a PC. So it's probably reasonable to think that someone would have access to saved game data. When creating the game, I never really cared about protecting the data. I figured that if the game actually was popular enough that someone wanted to hack it, I'd consider that a success in its own right.
I save a file called "MyCapturedRegionCount.sav". It's four bytes (one integer) long. I'll give you a million dollars if you can figure out what data is stored in that file.
Someone apparently already figured it out and edited the file, and now we have a new surprise leader on the Hall of Champions! Previous high score was 550 or something. New high score? OVER 19,000! So much for subtlety.
Since discovering this, I've gone through all kind of emotions.
I'm angry, because one person is ruining the integrity of the game, and potentially costing me bad reviews, lost sales, and lost income.
I'm disappointed that someone would want to take a good thing and ruin it, just because they can.
I'm immensely proud that I've actually created a game that someone cares enough to hack.
I'm intellectually challenged, and want to fight back with encryption and checksums and so forth.
I'm defeated, knowing that whatever safeguards I put in place, there will always be a way around it.
I don't really know how to proceed, so I think I'm just going to wait and watch and see what develops. When faced with conflicting options, I've found that "do nothing and see" isn't a bad one.