Somehow I never saw this thread, but I have a few things to toss in here.
*I have friends that are pinned by SigEps from three different WI chapters. NONE of them have ever sat in on any rituals other than those open to the public (like Burning Heart). About half my active chapter is pinned or about to be to a SigEp, so I think I'm relatively knowledgeable on the situation.
*ZTA-Mom, I think that tradition sounds really cute, and I'm sure her chapter would have a candlepass for a tagging, since it sounds just like lavaliering to me.
*I think it's amazing how much this varies from campus to campus - I know lots of girls from Platteville who were pinned, hardly any at Marquette who are, and my friend, who is outgoing president of his Phi Tau chapter, had never ever heard of pinning until I mentioned it.