It does happen
My class is ESL, so they tend to do it in their L1, though.
One of my coworkers teaches eighth grade English, and apparently last year she had several kids who would say really out of line things to her. That was also the year she had to take some time off midyear because the stress was intolerable--and she is a very experienced teacher. This year has been better for her. When someone asked how she was doing at a meeting, she told us very brightly, "Well, no one has told me to **** myself yet this year!"
If it's a one-time thing, I would do what you did--refer the kid, and forget about it. If they keep it up...well, different problem.