Business dress (i.e. badge attire) = no jeans or t-shirts. You don't necessarily have to wear a dress. You can wear a skirt or slacks. As far as khakis go, some girls in my chapter do wear their badge while wearing khakis, but they dress up the khakis with a nice top, jewelry, etc. I would say that it would be best not to go with khakis unless you were going to dress them up.
I am wearing my badge to my 8-5 job tomorrow but won't be wearing it to my evening job (at Target). At Target I will be in khakis and a red shirt, nothing dressy, which makes me sad because I really wanted to wear my badge all day. I miss wearing it.
