Also, I imagine she would be a transgender in a sea of cosplayers. I can see the confusion.
The sheer amount of women in male character and the occasional man in female character can be surprising at any popular convention with cosplay. The odd dichotomy ends up occuring where if you notice the costume, but fail to address them and demand a picture, you can get labeled as a creeper loudly. If you fail to notice when someone does bring out a camera for pictures get labeled as a photobomber or douche. If you fail to recognize the paid models from the fans, you will be in for a bad time as well and so on. Trying to pile on with trying to guess actual gender seems fantasy realm times (although the announcer hosting the event is another relatively non-issue entirely).
I'm hoping this sort of thing isn't becoming the norm at all conventions and just the odd coincidenses that I've experienced at the last few I went to. Although I did have someone dressed up like a ninja stalk me through half the convention hall for the better part of 30 minutes as well before (stab?) poking me in the back and then running off the last time i went to one...