X-acto Knives in the High School Art Classroom

Last I wrote, I mentioned at the end that there would be an X-acto knife classroom story. Since that happened so long ago and is now at the bottom of my list of stories to tell of things that have happened in my classroom, I will give you a quick synopsis.  
-Teacher assigns cardboard relief sculpture project
-Teacher teaches appropriate and safe use of X-acto knives to cut cardboard shapes
-Student takes X-acto knife and jokingly holds blade-side-up to another student's neck and says "here....let me give you a tattoo" 
-Teacher takes X-acto knife and disappointingly asks "are you out of your mind?"
-Teacher writes a referral to an administrator 
-Student says, "no...please don't write a referral"
-Teacher calls parent about situation, parent is supportive about current consequence
-Student is suspended and a tribunal is scheduled for further consequential action
-Parent claims the consequence is now too harsh since he was only playing
-Tribunal is cancelled, student is dropped from my class

There you have it. That's it. Many mixed feelings go through my head about this situation. The other 70 students working with the X-acto knives in that same course had no issues and made beautiful relief sculptures.  They learned a great skill and created something cool.  I stand on that to remember why I do what I do.