At my school, here was the attire for the week:
Open House: sundresses, casual slacks and tops, capris
Philanthropy night: recruitment t-shirt or short-sleeved t-shirt and shorts
Invitational Night: sundresses/casual dresses, skirts, pantsuits
Preference Night: the website says dresses, and most of the girls wear little black dresses.
I don't think brand names played a huge part in recruitment, but again it depends on your school. There might be a house or two that looks for those, but my sisters and I compare our fake Gucci handbags for fun