You've never encountered one of Windows Installer's many bugs? That Control Panel is nothing special, it just runs whatever uninstaller the program had whether it be a Windows Installer one, NSIS, Inno etc. So - technically - it can't fail; being a simple program launcher.

As for the uninstallers themselves, believe me, I've had many fail on me. "UNIST.LOG not found; Insert original CD and select file that happens to be in some obsurely named CAB file"