http://gameological.com/2013/05/inventory-9-games-with-creat... (it is the first one)
More details & discussion from Game Dev Tycoon's developer blog: http://www.greenheartgames.com/2013/04/29/what-happens-when-...
[1] http://www.quartertothree.com/game-talk/showthread.php?42663...
With non-gaming software the situation is completely different. When a cracked version craps out the prevailing sentiment is always that it was a bad crack. Always.
I'm wondering why there isn't a service that lets you search for people encountering your crack-penalty. A really sneaky company would disguise itself as a hacker group, then offer a copy of the game that doesn't have that "bug." (But has another one.)
So you're balancing making it hard for crackers to detect, and easy enough for players to encounter that shift behavior.
https://en.wikipedia.org/wiki/The_Settlers_III