The problem with that approach is that not all transgender people elect to have operations, so making that the minimum bar is unreasonable. A much more reasonable (non-fear mongering) approach is to use the gender the person identifies with. I don't know how you set that bar, maybe it's obvious, maybe it requires a note from a physician or similar.
I think it would be fairly obvious to discern someone who's actually identifying with a given gender versus some guy who wishes to get into the women's restroom.
I think it would be fairly obvious to discern someone who's actually identifying with a given gender versus some guy who wishes to get into the women's restroom.