They've suspended her and will most likely make her move schools. Could they fuck her life up anymore?
To me this seems like they are making a mountain out of a mole hill. My father is a diabetic, so I'm very familiar with the device she used to 'stick' her friends with (by the way, what an AWFUL description by the author of the device).
These things are nothing more than toys for little kids, shit I used to dick with my dads too (although he started requiring insulin when I was a teenager so I knew about the dangers of contaminated blood and only used clean needles to poke myself). For those that aren't familiar with these 'pens', how they work is inside is a disposable needle about a half inch long. At the end of the 'pen' is a type of spring loaded button or level that 'cocks' the 'pen'. On the side is a little release button that releases the spring driving the needle down the pen poking out the end. What's so fucking funny about all this is that the needle only comes out a millimeter or two. Only enough to break the skin and allow diabetics to get a little blood droplet so they can test their blood levels. That's it! These wankers make it sound like she ran around with a box cutter.
Gawd, I remember once in Junior high we went through a fad at our school making blow darts out of shoe lace tips and pins. Using an empty pen tube as a launcher would give you an effective range far larger than a small classroom (much to the nerds dismay). Worst that came of it is one guy got suspended (for his malicious intent in that specific incident) and the rest of us got a lecture on how we could have put and eye out. We felt bad and moved on. And that was grade 8 ffs and we knew better! this kid is in grade 3.

What should have died as just another dumb kid incident will now haunt this kid for years as she tries to get away from the stigma of being the girl expelled for stabbing other kids and giving them AIDS (you all remember how vicious little kids are, and they could give a fuck about truth).
IMO, what a shitty school principal. Too busy looking out for their own ass, to think about the damage to this childs life. Also in my opinion a simple discussion with this girl on what she did and the implications of it would have done FAR more to build her as a person than expelling her and forcing her along.