Since I last did any tagging in this area, the wiki has been updated to mention the skunking of the unisex tag, and that it should be accompanied by gender_segregated to distinguish. Is this still the case for bathrooms marked as gender neutral with only one occupant at a time? I wasn’t sure how to deal with those since there’s no other users to be “segregated” from, so to speak.
According to the wiki:
Used for indicating whether a feature has separated male and female facilities.
So if both sexes are allowed to use the same facilities (even if not at the same time) then that’s gender_segregated=no.
I agree gender_segregated is a weird tag. no doesn’t tell you that the facility is co-ed, just that there are not totally separate facilities for each sex, and yes doesn’t tell you whether there are private rooms available, just that some of those rooms are restricted to male/female only. Outside the specific situation the tag was invented for (as a and_by_unisex_I_really_mean_unisex=yes tag) it’s not all that useful.
If you wanted to map each restroom individually unisex=yes + gender_segregated=no + capacity=1 could work to explicitly indicate the presence of a private room that can be used by anyone, but for other capacity values I don’t think there’s currently a way to tag that.
See also Gender-neutral toilets in combination with male and female toilets? (and particularly reply #17).