Socially it depends on how well they manage to disguise themselves as male. Being visibly pregnant is a very obvious indicator that a woman who is attempting to present herself as a man is not actually a man.
What does this mean?
At my workplace, one of my male colleagues calls himself "non-binary" and has "(they/them)" in his email signature. He looks like any other man to me.
As far as I can tell, it's more like a religious belief than any kind of distinct visual style.
And “visibly” as in I get funny looks and sometimes shouted abuse from passing cars. Is that enough for you?
My male colleague who self-describes with a "non-binary" identity has no obvious visual markers of this.