A buddy of my 16 year old son just got expelled from school last week for a similar joke.
The kid was on Instagram trading bad jokes with some other friends. After one especially bad joke, the boy responded, you make it hard for me not to be a serial killer.
Two days later, he was booted from school (a rather expensive private day school) because someone that saw the post reported him to school authorities. They said they were uncomfortable at school now.
And, the kid was a week away from his Eagle Scout Board of Review.
Pretty bad situation all around.
Years ago my daughter made a comment at school. It was stupid and could have been taken as a threat. Suspended for weeks, had to be evaluated by a therapist (she was not a threat, but had other stuff going on).
It was a long haul but she was studying during her weeks off and the therapy got to the root of her problems and was very helpful. If not for a couple of her teachers and a good friend/therapist/former teacher (all in one!) sticking up for her at the numerous meetings with the idiot Principal and idiot school guidance counselor it could have been pretty bad.
My guess is a girl would have been given a stern talking to
by the Assistant Principal, then told to go back to class.