Seeing this reminded me that my sorority did a "Phi-esta" mixer. It was after my time, but god bless Facebook, so I went and looked at the pics. No boys were pictured (because it was for our official fb page) but all the costumes I saw were just colorful ponchos, peasant blouse type stuff. I think a group dressed up as a mariachi band. On the other hand, we always were known as the "boring" "lame" group--I guess non-racism is boring and lame. Chi O always did a "Cinco De Chi O" but I think it was more of a formal and I don't remember any rampant racism there. So it can be done.
On the other hand, Panhel had to ban the "____ and ____ Hos" mixers ("Bass Pros and Fishing Hos" "Tennis Pros and Country Club Hos"), because, Yikes. So instead it was a "Fishing" mixer and a "Country Club" mixer, and everyone wore whatever they were going to wear anyway. Sometimes college kinds make me
--but I also remember getting outraged over the "ho" ban...