This subject came up in another post and I wanted to start a new thread to see
where everyone stands.

Situation: A pretty and passable twenty something male attends
a vanilla dating event dressed as a girl. She blends in and is chatting with several of the men present, although not leading them on.

Questions: Does she have an ethical obligation to tell a man she is not really a girl, and if so, at what point and how to phrase it?

Here's my answer, but there will be other valid points of view to be articulated.
It's a vanilla dating event so there will be some less than highly evolved males there looking to meet women. They will assume heterosexuality and may have already had a few drinks. To not tell a man the truth is a lie of omission which may cause him to lose face in public and respond with violence. Further, it makes even flirting an unconsensual act which could be seen as just using him for her amusement, perhaps justifying or amplifying his homophobia. If she goes farther, it's in the same category as rape.

At well over six feet tall, I'm not passable and do not seek male attention when I'm in public but if I were approached, I would say sometning like: "It's my first time out dressed as a girl." Which it isn't but now he knows the score and can decide whether he wants to continue. Also, if I were passable and if I wanted male attention, I would put up a profile on a trans dating site. Anyone who reads my profile would know the score up front.

So girls, where do you stand on this? Please chime in and keep it respectful.