Anyone ever work for a locksmith?

I was tired of getting someone else to open a door for me and wanted my own key. In order to duplicate a key that says "do not duplicate" you must bring a letter on letterhead to a locksmith. My boss doesn't care if I have a key, she just doesn't want to be asked to do anything more than she already does. So I went back to my office and wrote a letter on letterhead and signed my name on it. I have no authority to request such a thing, but I gave the store what they needed and they made me a key. In retrospect I'm a little worried that the letter will get back to my boss and I'll get in trouble. Where do these letters go?