I had this realization during one of my later linguistics classes. It was a syntax class, so didn't really have anything to do with pronunciation; but it was an upper level class, so it was a safe assumption that everyone knew IPA.

In the beginning of the class, the professor introduced himself with "my name is X, but you can call me Y if that is too difficult". The two names were mostly the same, except that the first sound in X was a complete mumble, where I could not make out what he had said (and he repeated it several times). Later in the first class he handed out a syllubus which included his name in IPA. I immidietly knew not only how to pronounce it, but was able to do so without any difficulty.

(For those curious, his real name started with /ʒ/, while his nickname started with /dʒ/)