Snarky comment about not being able to gender women correctly aside, no, there aren't very many cisgender women who have trouble passing - but there are some. There aren't very many of us either though, passing or not:
1. Women with serious PCOS - some of them are fairly masculinized with significant facial hair.
2. Breast cancer survivors who've had double mastectomies and don't use prosthetics
3. Androgynous women whose slender bodies and short haircuts aren't really butch, but people question them, especially if they are tall
4. Taller women - there are girls who are taller than 6' 2". I watched one get accused of being trans at a city council meeting. She wasn't trans though.
5. Intersex women - there are conditions that can leave women somewhat masculinized.
6. Butch lesbians - or simply masculine straight women.
There are other examples, and I'm not saying that I have trouble telling the difference - I'm talking about people who really
don't understand what trans people are, what we look like, and how to spot us, when you can actually spot us. I think that neither I, nor any of the members of the forum are likely to point out someone who might not pass in a women's room. I mean, c'mon.
Basically, if you set the standard for what a woman should look like to be whatever some random person thinks a woman looks like, you are going to have problems, because some small percentage of cisgender women are going to get called out by some people. It is probably more likely to happen if said people have been whipped up to where they see a trans person in every bathroom stall because of a witch hunt.
The vast majority of women will basically pass all the time, without issue. But there have already been reported cases where cisgender women are misidentified as trans when they are in a restroom, or other public place. I can post links, if that's necessary, but these things aren't hard to find, and while they may be rare, they happen, and they spotlight the danger of sending out peasants with torches.
I do apologize if my comment was misconstrued to be about all women, or even any of the cisgender women on this forum. I haven't seen any photos here that I thought would ever be at risk of this. But it has happened at least a couple of times around Dallas, and in some other places as well. I'm sure more of them happen than are reported, because I can't imagine how mortifying that must be - to be accused of not being a woman. Oh wait a second, I actually *do* know what that's like! Anyway, it sucks. I personally think that some poor woman with a hormonal condition doesn't deserve the grief I get. Heck, I don't think *I* deserve the grief I get, but it just breaks my heart for unlucky cisgender women who face this once in a while. I do really mean that sincerely, I wouldn't wish that on anyone, but it really does happen to some women, and I think it's just horrible. Random bathroom occupants need to stop acting as the "potty police".
Is the reason to argue about this? Surely if we can agree that cisgender women shouldn't have to worry about the humiliation of getting called out as being trans in a restroom because they have an unusual appearance for reasons that may be totally beyond their control, and because the person calling them out is an idiot? Seriously, I can post links if you don't believe this is a thing that can happen!