Good idea about getting her to leave something about it in her will.
My guess is that no one knows it is out there because this founder never had children. Her relationship as a "grandmother" to my mother-in-law is by marriage only, so it is understandable that she would not be linked through any genealogical search. At the time of her death, the pin was given to my mother-in-law because she was the only other DZ in the family and it meant something to her. This was many, many years ago before Ebay and before the issue of who a pin belonged to cropped up. I don't even think my mother-in-law has thought twice about it. She just showed it to me one Christmas when we were talking about my sorority.
My husband, however, is an only child, so, in the event of her death (presuming we are both around) I would make sure that the pin is sent back to DZ HQ. I just think it would have been nice for her to have made a presentation at the DZ convention last year....wasn't it DZ's 100th anniversary? At any rate...maybe by the 125th anniversary I can talk her into it. heehee!
Thanks for the advice.