I just think it's already such a well established hand sign for hang loose and Hawaii, that it seems odd to use it as "our sign".
Besides, this rush to get our own sign makes us look like we're trying to be like the Yewts. Like the "3rd Down Stop" and naming the ROC a few years after the MUSS was created. I think we can and should start our own things/traditions. I've been going to medical school at the U and get tired of hearing how we're trying to be like them.