My prediction

[S910441]

Male child comes into school and announces that they now identify as a girl/cat/clown/cheese grater, etc. Peers and teachers too scared of repercussions to question this behaviour, so individually and collectively affirm child's new identity. Parents do likewise.

This continues for some time.

Eventually it transpires that this change of identity was precipitated by psychosis, was a symptom of a serious mental disorder, and that, owing to uniformly unquestioning affirmation, the window for early intervention has been missed. ("Getting help quickly is really important if you're experiencing psychosis," according to the NHS.) Treatment is therefore far more lengthy, difficult and traumatic (and expensive for the NHS) and many disruptive years of psychiatry and periods as an in-patient in psychiatric wards follow.

AIBU?

The problem you're describing is more akin to mass hysteria. Beliefs are contagious and spread very quickly this is why they tend not to report suicide methods when someone has taken their own life. It's how people become brainwashed in cults. The human mind is vulnerable due to its complexity.

Well I suppose that's sort of comforting in the situation I'm envisaging. In a sort of ironic way.

I think that makes a lot of sense. It's certainly very concerning how it spreads.

The problem lies with the adults encouraging these false beliefs. Children often have fantasies and it's a normal part of growing up. My youngest ds pretended he was a cat for about 18 months. We were expected to go along with it, which we did, but if he'd displayed any inclination to take things further than let's pretend, we'd have cracked down on that right away.

Adults who encourage and facilitate children in living in a fantasy world have no business being around children.

Totally agree!