Why? https://discussions.apple.com/thread/1292165 and many other priors are out there on this.
http://rdklinc.com/answers/discussion/341/removereset-open-firmware-password-macbook-pro-core-i5/p1 covers a workaround but newer models fixed that for more security.
My macbook showing padlock on screen. I tried rebooting with command r

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