For What It's Worth, I have and wear a kilt from time to time. Plaid of colors of the local sports team. As an experiment, I loaded up the panniers, donned a backpack, threw on some cycling shorts under the kilt. All in an effort to play into the image a motorist would probably have of a fit female commuter. There was a noticable change in driver behaviour. The cars approached from the rear slower. They gave a wider berth when passing. The only thing that changed from their new found cautious behaviour was how hard they stepped on the gas pedal when they saw my big bushy beard and realized I was a dude!

Drivers do indeed treat cyclists differently based on whether or not there is some relate.