In my past, there was a time when about 20 - 30 % oft the people around me were trans in some kind of way. Mostly not transitioned people, but people "feeling sometimes male sometimes female", "feeling like they were both", "feeling neither nor but being neutral" etc. It was'nt a fashion, it was 15 years ago and they did not have more concrete words for that, and it was really their gender identities, not some whatever being seen as cool. It was constant, most of them were neighbors of mine... Mostly living in the same house, we were 24 people there, most of us students. We just happened to have found one another and made friends. It was not within a "gender scene", but had just happened, a little nest in the province... Which made me believe for the next couple of years that being gender-variant in some way affected about 5 % of the population, and was absolutely normal, known and unspecular. However, after lots of funny and clueless reactions to my pre-transition coming outs I learned that no, it's not.

Well one of them was a non-outed transwoman. We had an affair later on and slept with one another, and well, I don't wanna go too much into details, but methought she really was trans as some body parts were okay to her being touched, others not... She never said openly she was trans, but complained openly about her male features and said she was happy to be called "XXX", the short form of her forename, as "at least, that's neutral". She often was called with female pronouns half-jokingly, half-seriously by her flatmates(as people around her sensed what was going on), and she never objected to it, but was happy about that and even said that, as "this fits better". And she complained about being mistaken for a gay guy all the time, as her body language was more than flaming. Flaming gays I knew very well as I used to be in the male gay scene then, but she was different. The only two guys from the gay scene I ever knew with a body language comparable to hers, well one of them said openly he's a transgender, a woman in a man's body, with body dysphoria etc., but he had decided to live as a gay guy, and the other one was flaming as hell and had serious hormonal problems, his body was very under-developed, I never asked him for details but would have loved to send him to shrinks to get that checked up. Me seemed, there was some intersex-stuff going on or testosterone did not work well, plus a non-male gender identity. I could "smell" that.
Well this transwoman neighbor behaved and thought like a girl, wore almost only unisex clothes (and openly stressed that fact!) and complained a lot when having to wear a cravat though she was conservative. Obviously did not feel at ease in her skin etc. A mirror image of me. Gosh. Sad she dumped me. I think she did not get along that I "read" her clearly. During the short time we were together, some of the other people in the house grinned at us as we made a weird impression, like the queerest straight couple you could imagine. The gender-variant people did not do that, they kind of knew what was going on with us, but were okay with it. However, she never denied or admitted openly that she was trans. But I'm sure she was a she.
Once I made the horrible mistake in front of a bunch of people - after a couple of drinks - to out her after she complained of being mistaken for a gay guy as she was not interested into guys: "You're a woman in your brain, so you cannot be gay, at best you could be lesbian, you're just like a transsexual, just like me, but you're the other way round, and you don't do anything with your body, just like me. We should change bodies, then we would be happy".
And she went like "Ooops" and got red all about her face. Afterwards, I felt like ->-bleeped-<- for having outed her like that. I was already out as "feeling mostly like a guy but in a female body" there, and the people at the table were our neighbours and they were used to the "gender variant" minority of our house. So I had no idea it might be a hassle for her. But she was not clearly out, she just made obvious hints all over the time, without saying anything clearly, in whatever words. So I probably forced the outing upon her without her okay. Ouch. I thought it was so so obvious from the hints she dropped all the time that I thought she was out anyway, but some of the people of the house did not really get that. The "gender variant" minority got it, the others didn't. And that was what I found out when we were all sitting at the table, me outing her. Ouch.
Another situation was about one month ago. I was in the tram, two Turkish women entered them, dressed the usual western style + kinda sexy (lots of Turkish women have that metropolitan style here). And my transdar is good. They sat around me and - one of them is clearly a transwoman, I thought, the other one I'm not sure but might well be. I looked at the hands, chins etc., all that stuff which gets transformed if testosterone does its work. Anyway, both had a great passing, clearly female way of moving etc., no one else in the tram raised an elbow. Then another Turkish woman, traditional muslim clothing, headscarf and boring grey gramma-style clothes, entered the tram and sat down near them, and they knew each other. And the "clear case" started having a conversation in Turkish with the other woman. In a tenor/bariton voice which had obviously been very well trained by logopedists. Holy moly, I thought, my transdar ist better than usual people's.
I don't understand any Turkish apart from a few words, so what I got from the conversation was a bit like:
"Yüsgüldarün yamislarün +(Name of my endocrinologist."
"Yagüldarin yüsürimalya +(Name of my endocrinologist)."
"Yürilmayun yusgürildayin (Address + Name of my endocrinologist)."
etc.
My endocrinologist is where all the trans people go. The other western-styled woman, who was maybe trans, just kept silent all the time. Maybe she was shy, or God knows what voice she had or thought she had. The oriental-style elder Turkish woman seemed cool with the topic all the way through. Wow.
I was close to outing myself. But I didn't do it. The clearly trans woman was probably out to the traditionally styled Turkish woman, but she might have felt pissed off being outed in the tram in front of all the passengers. Or being "clocked" even by her own folks. Plus neither her nor her "unclear" friend (they both later left the tram together and then went through the city together) had apparently clocked me, they just ignored me all the way long, I must have seemed to be some random teenage boy for them. Though I'm 35.
It was a weird situation, and I found it best to just keep silent there.
I wouldn't suggest outing anyone. Usually they want to keep control about their outings, be it pre/without, during or after transition. And no, we're not all friends just for being all trans.