Peanut as proven by Man Friday, the police would be called immediately. This about oppressing and subordinating female people and their spaces. It's about ownership.
What will happen is what we've predicted from the start: the girls without sufficient privilege to cope will be forced out of the space and lose access to toilets. They won't drink. They'll miss school when they have periods. They'll do whatever is necessary to not have to go into the toilets. They will be in massive majority girls with protected characteristics and vulnerabilities who are more marginalised than the yippee I'm all right Jack I can wash my hands covered in blood and be fiiiiine female people.
It isn't socially just. It's misogynist, it's sexist, it's unkind, it's uncaring, it's insensitive, it's exclusionary, it's discriminatory, it's regressive.
In a few years, people will start going..... hang on a minute, we've got an issue with girls.
But #theyreonlyfemales