CommandOptionPower is the KeyboardClaw of almost final recourse on a Mac, and the Macintosh world's version of the ThreeFingerSalute. If that claw doesn't do it, you look for a power switch or cord to unplug for a brief TimeOut when your Macintosh is being a bit pesky.

Actually, it's command-control-power to reboot; command-option-power puts the machine to sleep (on recent machines). 
Command-option-escape forces the current application to quit, which might be the source of the confusion. -- A long-time Mac user who hasn't got round to MacOsx yet

See also CommandKey.