Transphobic billionaire author J.K. Rowling has encouraged random people in the United Kingdom to photograph people in women’s restrooms just in case they are transgender. Her advice is likely to result in the public harassment of cisgender women who don’t fit people’s preconceived notions of how a cis woman “should” look — such harassment has occurred many times in the past.

In a Saturday post on X, Rowling noted that someone asked her, “How are you planning to police public toilets” in light of the recent U.K. Supreme Court ruling that the legal definition of men and women in the country’s anti-discrimination law is based on biological sex…

In response, Rowling said that policing trans people in public toilets can be handled, “Quite easily, really. Decent men will stay out, as they always have, so we can assume all who don’t are a threat, given their disregard for women’s and girls’ safety, privacy and dignity. Photographing, reporting and disseminating such men’s images online will be a piece of cake.”

In the U.K., it is generally illegal to photograph people in restrooms.