Unfortunately I've heard of a trans identified woman who lost an ovary after presenting with abdominal pain which was misdiagnosed as appendicitis).
As they were "male" the differential diagnosis of ovarian torsion wasn't considered and was only identified at delayed laparoscopy (It's safe to wait to operate on an appendix. If ovarian torsion had been considered an US would have been carried out). The person who told me about this case said their true sex was only discovered when the team inserted a urinary catheter (routine for laparoscopy) pre-op and they had no penis.
There is also the case of the trans identified female who wasn't pregnancy tested before their gender re-assignment surgery in Australia.
I've also had to deal with a lengthy and involved complaint from a trans-identified woman who felt that being asked to comply with our pregnancy testing policy pre-surgery for women of child bearing age was discriminatory to her gender identity and transphobic. The fact that trans identified women in a US cohort have a higher rate of unplanned pregnancy than an age matched non trans cohort didn't cut the mustard as an initial explanation.
So I can see why some trusts have decided to just ask everyone. Less chance of making a mistake.