"We've seen literally thousands of these kinds of episodes of zero tolerance since the early 1990s," said Skiba, who co-authored a 2006 study for the American Psychological Association that concluded zero tolerance has not improved school security.
In the Pennsylvania case, Guarna, a former police officer, said she was summoned to her daughter's school last month and told that 5-year-old Madison had talked about shooting her pink bubble gun.
The kindergartener was initially suspended for 10 days and ordered to undergo a psychological evaluation, according to documents supplied by Guarna's attorney. The suspension was later reduced to two days, and the incident was reclassified as "threat to harm others."
But Guarna wasn't satisfied. The counselor who evaluated Madison indicated she was a "typical 5-year-old in temperament and interest." Guarna and her attorney, Robin Ficker, demanded the district expunge Madison's record, apologize and make policy changes.
The parties met recently and Guarna went away happy, though she said she was asked not to reveal the terms of her agreement with the district. The district's attorney declined to comment, citing privacy law.
Guarna said she intends to push for changes in state law.
"My daughter had to suffer. I don't want to see other kids suffering," Guarna said.
Mark Terry, a Texas principal and president of the National Association of Elementary School Principals, said most principals he knows are "not big supporters" of zero tolerance policies because they discount professional judgment.
But when discipline policies do provide leeway, he said, "I would hope that principals would, number one, use discretion and common sense. And if you do make a mistake, apologize and say, 'Hey, that was a boneheaded move.' Our sensitivities are just too high and we need to back off a little bit and take a look at what our real safety plan is."