Does Apple do anything at all to prevent OSX piracy?

Noting that this isn't a how/where piracy thread, I'm just curious.

Windows has various ways to detect and bug pirated versions, even if it still "works" after it's detected it will change your wallpaper etc, and I think with the new ones may do some other stuff.

OSX on the other hand, it doesn't ask for a unique activation key, it doesn't seem to phone home at all. Does Apple do ANYTHING about OSX piracy, or do they just let it get out there as fast as possible even if some people don't pay?