That's great... I'm an alum, and I still get super-excited whenever I see letters on cars (I'm pretty far away from any Phi Mus now, sadly) ... and if I see letters in public I always make a point to go up to the girl and introduce myself! They are usually as surprised and excited as me! Once I even left a note on the parked car when I discovered a Phi Mu sticker on the back (I was on vacation in a far-away town) just to say hello and LIOB!
When I was still an undergrad, I had two neat encounters. I worked as a student assistant in an office on campus and...
1) We got an awesome new employee. I just had this feeling about her! Come to find out, she was a graduate Phi Mu from another school that had just moved to town! When she told me, I had to laugh because I just somehow already knew without her even telling me! and...
2) One day, a lady came into my office to inquire about some things for her son, and she saw my lavalier and excitedly told me that she was a Phi Mu, too! (she had been one in the early 70s!) We struck up a conversation and talked for about 10 more minutes. Yes, The bond exists everywhere... it's something we all share in our hearts. So cool!