I have a story that kinda fits! Never shared this before, but I'm sure many people have experienced something similar.

Anyway, this was long ago in kindergarten. We had one teacher who, for some strange reason, hated it when kids went to the toilet. She'd track who went to the toilet and ask us kindergardeners things like "didn't you just go when I came in" or "why do you always need to go when I'm teaching".

Oh and this is necessary context for later - our classrooms had louvered, transparent windows along the corridor, and the windows were usually kept open, so you could look in easily from the corridor.

Some of us figured out that it was easier to hold your crotch and make a pained expression every time we needed to go. We'd just say "I really need to go" and hop around and she'd relent. But after a few too many people did that she got angry and declared that nobody could go to the bathroom twice in her class and started writing down the names of kids who went to the bathroom. If your name was on the board you couldn't leave the classroom again.

So one day, one of my brilliant classmates asked to go to the toilet, then brought his workbook and pencil out with him. When he came back, he stood outside the classroom listening to the teacher.

Our teacher asked him to come in. He said "but if I come in, I can't go to the toilet later."

Of course the teacher made him come in and changed the rules after that. But I'd like to think this kid became a lawyer.