Of course, if you actually started using this method to put up a nag screen, the pirates would just remove the integrity check too. I would imagine the only reason it's even possible is because the game works fine and the pirates didn't notice the flag.
I'm not sure this is true, or if it is true, it might not be true in the way the original guy who wrote the story mentioned. He said his app was up about 40 minutes after launch on a pirate site. I get the impression that what you download from Cydia rewrites the system calls, once for all, and does not rewrite each app internally. These apps are distributed binary, yes? So you're going to need a cracker with a disassembler, iphone dev kit and some time to pull out the internal checks. This opposed to doing it once for all on the iphone OS side. I'm betting that's how it's done, and if that's how it's done, then adding those checks will have some impact.
The info.plist file is a plain xml of key/value pairs of properties that tell the OS how to handle the app, which kind of files can be opened with it etc.
AFAIK, the application that kids use to crack iPhone apps adds a key/value pair to the info.plist which is needed to load the app on a jailbroken device. So, you just need to check for its presence. If the key is there, the app has been cracked.
I understand how it works, but my point is that if you use this check to shutdown the app or constantly nag the pirates, they will simply crack the game to remove the check. The only reason this guy was able to gather statistics was because he allowed pirated versions to continue to function normally.
Pirates have been reverse engineering and cracking Windows Mobile games by hand like this years.
I think you're right about it being a mostly automated process right now -- but don't think making them doing a little work will scare away the pirates. I bet there are lots of kids in the iPhone warez scene looking for a challenge.
I did some research into mobile app piracy 3 or 4 years ago and found a thriving scene for cracking WinMo, Palm, and J2ME apps and games. And these were not automated cracks, someone sat there with a debugger and reverse engineered the registration keys.
