Indeed. "Smart people" abusing undocumented behaviour of Windows releases is usually the cause of compatability problems when a newer Windows version is released. You can read a few articles on Raymond Chen's The Old New Thing to get some understandong on how far Microsoft had to go to make sure that old programs doing stupid things kept working in new Windowses.

You don't abuse undocumented features of your environment as a developer. It's always a bad idea, it will always inevitably come back and bite you (or even worse, your users) a few years later.