I was not a music major, but I pretended to be one.
I needed "an easy A" to bump up some unfortunate grades, so I signed up to take beginning piano. Only music majors could have a student job in the music library, but the same friend who convinced me to take piano introduced me to the librarian as "a piano student," which the librarian apparently mistook to mean a real one. (Actually, her big concern was whether I'd be prone to killing the African violets that filled the place--the last student librarian was apparently a klutz.)
Since I could do all my listening homework while I worked (the librarian had a convenient headset with which to plug into the reserved music . . . with about a 16-foot cord, so I never had to take it off), I started signing up for music courses right and left. The librarian also had dibs on the keys to the good piano rooms after hours, so I practiced in one of those. Nobody could hear what I was slaughtering, of course, so they went on for years thinking I was a piano major.