I was out at a local market in Southern Vermont today. When I got to the checkout line things were pretty congested. I got in the shortest line I could.
A minute later, the next register over opened. There was still one more person in line in front of me (a woman in a dark red skirt suit) who hadn't noticed the new register, so I tapped her on the shoulder and said "Ma'm, That register is open now" to give her a chance to get to it before I skipped over.
She was wearing a dark red skirt suit and had long black hair (not a wig) and a purse. As soon as she turned toward me there was no doubt that she was not a GG. She was wearing no makeup and had very male features. She said 'thank you' and moved to the new line. Her low voice also gave her away.
She looked very comfortable being out, so I don't know if she was a CD who was very used to being in public, or perhaps a transgendered person who was fulltime. Either way, I hope she got at least a little smile at being called Ma'm.
To the woman I saw: If by chance you are a member of this forum, I'd like to say 'hi'. Mabe you remember the encounter.
PS: I took this as an opportunity to watch the people AROUND her to see how/if they reacted. From what I saw, nobody treated her any differently, gaver her odd looks behind her back, or had a word to say about her even after she had checked out and left the store. In this respect, it was a confidence boost for ME for the next time I'm out!