Readers of Raymon Chen's blog The Old New Thing may be familiar with exactly this sort of thing, which forced windows 95 to have the version number 3.95, instead of 4.0 [http://blogs.msdn.com/b/oldnewthing/archive/2004/02/13/72476...].

Making the libraries cope with bad programming is not good practice, but it is what keeps businesses using your software for decades. The Old New Thing really should be standard reading, because this sort of thing is barely the tip of the iceberg.

Other similar API avoidances that Microsoft have found programmers using to check things include obscure undocumented registry keys, API implementation bugs (seriously!), the padding data in tangentially related structures returned by API calls, and more