Mysterious Firmware Password set spontaneously.

I have worked a computer repair shop for 4 years and have dealt with some peculier things... Usually I hear the customer say, "I swear I didn't do anything..." Well this time it's true.

Some info that might possibly be contributed...?

I have my Macbook Pro /w Retina Display. I have a dual boot with Windows 8 that works natively, and in a virtual machine. About two months ago I dabbled with a Triple boot using Ubuntu Linux and so I had installed rEFIt to easily navigate the various operating systems. However, I moved the Recovery partition to a backup drive because of Windows' issue with installing on a 4th partition. (It complains about a max amount of primary partitions.) I have since removed Linux, but haven't returned the Recovery Partition.

So, my system is simply dualbooting.

I am used to using the option key to navigate between OSX and Windows, however for the first time I found that a Padlock symbol appeared after doing the usual option key hold. I have NOT set up a Firmware Password, nor is there anyone around this laptop with the knowledege to do so. The Recovery partition hasn't been present on this machine in a month, and I was under the impression that a Firmware Password was primarily installed via the Recovery partition, however I'm sure there is another way around that.

I called Apple, and they had some hash key, had me read them the last 16 digits of the code I get when I press Control, Option, Command, Shift, and S simultaneously. Then they informed me that they could not run their program for fear that it (the program) would be leaked to the public. They told me that I would either have to take the machine apart myself to flash the firmware, (something I am willing, but not wanting to do,) or drive the four hours to an Apple Store.

I am just pleading... I did not set this Password, nor did anyone else. What could have caused this MacBook to set a Firmware Password, and is there anyway I can remove it?

Thanks again, even if you just read it...

Casey