When I attend a civilian Halloween event, I dress like a woman on the street (and I don't mean a street-walker). For example, when there was a Halloween costume contest at work, I dressed in "office girl drag" trying to emulate how women typically dress for the office.
On the other hand, when I attend a trans Halloween event (like I plan to do Thursday evening), I dress in a costume that a woman might wear on Halloween. For example, for my support group's past Halloween parties, I dressed as a school girl, Marilyn Monroe, Jacqueline Kennedy, French maid, bat girl (photo right), and Playboy bunny, among other things.
For trans Halloween events, the answer is easy.
I dress in a costume a woman might wear because in the trans world, I normally dress as a woman. As a result, a "woman on the street" costume would not be a costume (unless I dressed like a street-walker).
For civilian Halloween events, the answer is more complicated.
I could dress in a costume a woman might wear for civilian Halloween events, but I never have.
Like many of us, my first forays in public en femme were on Halloween. Just dressing as a woman among civilians was a major accomplishment and the thrill of a lifetime of anticipation.
Dressing like a woman on the street rather than say a Playboy bunny, I might get fewer of those knowing looks that imply that I crossdress more often than just October 31. But I always femulate too well, not like the average guy in drag on Halloween, so I get lots of those knowing looks, but I'm not sensitive about it. If someone confronts me, I come right back with "Normally, I only crossdress on weekends" and they don't know what to say.
So, dressing like a woman on the street for civilian Halloween events does not buy me much with regard to fooling anyone about my proclivity to crossdress. However, the comment, "who is the woman (referring to me) not wearing a costume" never gets old.
I guess that dressing like a woman on the street for civilian events has become my personal Halloween tradition. That's my story and I'm sticking to it