My personal feeling is that you can usually tell. But the problem with people claiming that they can always tell is that they simply wouldn't ever know if they hadn't.
But this is generally only applicable to transmen as the very, very vast majority of transwomen just don't pass due to the effects of testosterone and there aren't really all that many having their faces peeled back for facial feminisation surgery.
Transmen have been described in extremes on here over the past week - they're always either 6 foot tall, muscular and with a full beard (so you can never tell) or 5'2 delicate things with tiny hands and wispy facial hair (so you can always tell). When the majority of transmen will fall between those two extremes.
But it's OK because the ruling made it clear that transmen who genuinely pass can also be refused entry to female spaces and that they are fine to continue to use male spaces for their own comfort and the comfort of other women.
And thats because, despite what the protesters would have people believe, the ruling was about protecting women's rights. It wasn't an 'anti trans' ruling and transpeople haven't been written or spoken out of existence.
All this post ruling trans rhetoric about big burly men being able to enter women's toilets and just claim to be transmen is nonsense because transmen who genuinely present as 'big burly men' shouldn't be in the women's spaces either!
And, as many people have said before, we've knowingly been using the loos alongside transwomen for years and most people didn't give it much thought as long as people were respectful. Its only been in the last 10 years that we've had a situation where we've had to pretend they were actually women and they have been allowed to have us kicked out of women's spaces or denied medical treatment or made criminals or sacked for recognising that they are male.
And had the language around womenhood (chestfeeding, pregnant people, cervix havers) changed. Along with the complete fetishisation of womanhood and gloats of, "I'm a better woman that you'll ever be because i perform femininity more than you do"
Alongside, the invasion of women's sports and the nonsense of people being encouraged and permitted to change their birth sex on legal documents and by the NHS which has resulted in ridiculous situations and death (TW demanding nurses perform smear tests on them despite not having a vagina or a cervix and a transman who died because she had registered as male and the hospital had treated her as such. This meant that they made the wrong diagnosis - via blood tests - and she didn't get the treatment she needed).
NHS hospitals that have changed the zebra crossings, which are black and white and easy to see for visually impaired people to rainbow striped ones, which aren't. Police dancing at Pride festivals and pretending they haven't seen male violence if it's committed by the right sort of man whilst visiting women who have used the wrong words.
People conflating LGB issues, which are about sexuality, with T+ issues which are about identify, which means that members of the LGB community have been negatively impacted by the trans demands because some people lump them all together. Or the T issues not being dealt with appropriately because, "This is just like people's attitude towards gay rights in the 80s," when it's completely different. And when the LGB Alliance was set up to prioritise the LGB without the T, the T went for them too. We've all read about the 'Cotton Ceiling' and language calling lesbians (never gay men) 'genital fetishists'. Young lesbians being coerced into having sex with transwomen with a penis for fear of being seen as 'exclusionary'.
The poor woman who was told they couldn't have been raped because she was on a women's ward and there were no men on there. When she knew she'd been raped and a year later it turned out that one of the women was a special new with a penis woman rather than be suppprted as a rape victim. Or women in courts who've had to refer to their rapist as 'she'. Or just general basic safeguarding requirements being ignored if the person breaking them was a transwoman or if a child said they were trans. Schools that were encouraged to socially transition children and not tell their parents (for safeguarding reasons in case their parents were TERFs). Parents who only found out their daughter was now their 'son' when they received the end of year report or went to parents evening - as per the DfE guidance at the time.
Many people don't actually give a shit about loos and would happily have continued to use them alongside men in dresses just having a wee and washing their hands (or at least tolerated it), which I think is why the loo thing has been focused on so much precisely because it obscures the actual issues.
It forces women to talk about the potential for rape and sexual assault which, whilst happens far more often than it should, isn't happening to all of us all the time. So the counter argument is always, "How many..?" And, "If a man wants to rape a woman, he'll just go into the women's loos anyway." And yes, one is too many but, like I say, it obscures the issues because the vast majority of women (whatever their experience elsewhere) haven't been sexually assaulted in a public loo by.anyone and that's what is always focused on.
So we now have infighting between women, women denying that other women can ever have a masculine appearance naturally; or claiming that you can always tell a transman when the likelihood is that you probably can't; or denying other women's experiences of being mistaken for a man when, away from trans threads, there have been several other threads where women have described being called, "Sir" and mistaken for men if they're taller, bigger and don't wear feminine clothing.
But this is all a result of the trans agenda.
People are scrutinising others more because the social contract has massively broken down and it has created a huge mistrust amongst women and probably some men. Women arguing about, "Well, where do women who've been through the menopause sit because they don't have periods?" Or, "Where do women who have severe hormonal conditions go because sometimes they present with more typically male characteristics?" Women's spaces. Because they're women!
What it means to be a man or a woman has become so extreme in some respects and based on being able to tell that we have people talking about all men being 6'+, having broad shoulders and a masculine jawline (when many aren't and don't) or women having tiny delicate frames and feminine features (when not all of them do) and we all know those people in real life and some of us are those people. So the debate ends up making some people feel ostracised from and by their own sex.
And now we have women with severe PCOS being challenged in women's toilets for not looking 'stereotypically female' enough and being upset with other women for that and other women angry back at them in return. And others angry because they feel women with hormonal conditions are being seen as 'ambiguous'. Whereas, previously, people would just have trusted that they were female no questions asked.
All the ruling did was give women back the right to say, "No," to men and not be forced and gaslit into pretending a lie is the truth.
The whole movement has caused such damage to people's perceptions, tolerance and trust in each other society at large and that is what is going to take time to repair.
It's.not just about toilets and toilets are the very thin end of the wedge.