As a Delt sweetheart at Tulane, I have an official sweetheart necklace the guys bought for me that I love to wear,
but I don't wear any DTD articles of clothing. There's no really official chapter policy on it, but I would feel akward with the on-campus culture to wear one, unless it was maybe a sweatshirt that I borrowed while I was out with the brothers at an event or something. Occasionally, they'll have 'sweetheart' shirts printed that they give out to women at parties, etc... but they're very hot commodities on campus, and I've never been offered one - it's more of a recruiting thing. I'm sure if I asked for one, they'd be happy to get me a shirt that actually said 'DTD Sweetheart' or the like, but it's just never been an issue. Only occasionally do I see any other women associated with the chapter wearing letters, either - and again, it's usually only in the context of borrowing a sweatshirt with the intent of returning it shortly, etc. etc.