No, I never put a true easter egg in anything. Especially in an operating system, I don't believe in them. You have to be able to trust the OS, and I think it goes against that.
As much as I can understand where you're coming from, easter eggs have always been thing in computers. From code in the Mac ROM to show if it had been wholesale copied, to code in the C64/128 ROM that showed the names of the developers, to more advanced easter eggs in Windows 3.1 Program Manager that displayed user names of the developers, to a reasonable facsimile of Tetris in Excel.
While your rationale does make sense, I think that leaving easter eggs behind is leaving behind a special time in computing history as well.