According to habitual liar Erin in the Morning:
"But at Long Branch Lagoon, members of the Kansas Compliance Crew resorted to having to describe their genitals to police in order to resolve the matter and avoid arrest."
I'm not sure, if the police did ask this, that it was the first thing the police demanded of them (it's a trans activist fantasy that people will have to look at their genitalia to work out whether they're men or women) and if they did ask it would only have been because they were being deliberately obtuse in answering other questions, but the implication would be that their female parts are intact.
As Erin points out, this law they were objecting to:
"purported to invalidate driver’s licenses of trans Kansans who had changed their gender marker."
So they could simply have shown their driver's licence to prove that they were eligible to use the women's toilets.
Clearly, the answer is for people's ID to correctly state their sex and for people to give clear answers about their sex. It's pretty simple so I'm not sure why OP is panicking. Although, reading the nonsense of Erin in the Morning does tend to induce hysteria and confusion.