I've often said that the problem with zero-tolerance policies is that they are a poor substitute for common sense.

But there's always the exception that proves the rule -- where administrators demonstrate they are so bereft of common sense that a zero-tolerance policy is needed to make up for this moral flaw.

This is a case in point.

Courtney Glowczewski has a small right arm and leg because of cerebral palsy, a disability that her teachers say has not kept her from working hard in school and being a good student.

"I do really good in my classes. My teachers tell me, 'Good job,' and, 'You're doing very good,' and 'Excellent girl,'" said Glowczewski.

But her physical appearance has made her a target of taunting and of physical attack, which she said has never been addressed by the administration at Martin Luther King Middle School. Last week, she said the bullying got worse when she said she was threatened and assaulted by a seventh grade boy.

"He pulled out a knife, a silver knife, a pocket knife, and then he said 'What!?' So I was scared and didn't know what to do," said Glowczewski.

As she walked to her seat she smelled smoke and one of her classmates was patting her hard on the back.

"I looked and there was a black spot on the back of my shirt. And then I saw some black hair falling from my hair," said Glowczewski.

So, a girl is set on fire and what does the school do? It tells her not to come to school for the rest of the year.

And what happens to her attacker? Who would appear to be facing multiple felonies (possession of a weapon on school grounds, terrorist threats, attempted murder).

7NEWS discovered that while Glowczewski was sent home, her alleged attacker is still in school, even though administrators confirmed he had a knife.

The principal has now admitted her staff did not call police, did not interview potential witnesses, and did not conduct a proper investigation.

Every administrator at that school who was aware of the incident should be fired for showing criminally bad judgement, and possibly face charges for failing to report the abuse to authorities.

This is why we have zero-tolerance policies, even with all of the harm they do -- some administrators can't be trusted to have common sense.