I was a music major in school and we had all 4 greek letter music oriented organizations. One of them is Phi Mu Alpha. As DZSAI girl mentioned in her post, many times music people are oblivious to greek life. Well anyway, some of the music girls we like Phi Mu Alpha groupies and they would shorten Phi Mu Alpha down to "Phi Mu" and tell people "Yeah, we're going to hang out with our Phi Mu boys" or "we're going to the Phi Mu" hayride. Being a Phi Mu myself, it used to drive me nuts. They did not seem to see the difference in the 2 organizations at all. When some of my friends from the school of music realized I was a Phi Mu they would say "Oh I didn't know it was co-ed...I thought it was all guys"
I was also a member of Tau Beta Sigma and people would pronounce the "Tau" as in "Tow" (like towel) but that's probably a common mispronunciation.