There is no such thing as a perfect diabetic. The body is too complex to explain at times. We've all had our days when we have an unexplained low and are caught off guard without having sugar. We've also all had days where we misplace or leave behind our cell phone, briefcase, favorite hat or purse. It is no different when a child simply forgets one day to take dex tabs or their meter to school.
Habitual problems are another story.
After the consequence, she was then on her own again. Yelling, or hitting, doesn't teach a lesson. I had a pretty bad reaction. Diabetics cannot always be held accountable for their actions when having a low blood sugar. Harsh words can sting, and although it is difficult, you must remember that diabetics are not in a sound mental state when they are low.