"It's a normal occurrence to have a heightened sensitivity after a high-profile tragedy, but that does not negate the need for common sense," he said.
Maryland father Stephen Grafton said common sense was in short supply in a case involving his 6-year-old son, who he said was suspended from White Marsh Elementary School in Trappe for using his hand as a "gun" during recess.
Grafton, a staff sergeant in the Army's 82nd Airborne Division, said administrators were criminalizing play. He said he told his son he shouldn't shoot pretend guns because it makes some children upset, "but it was a difficult conversation to have because he didn't do anything wrong."
The school lifted the suspension after a day and removed it from his record, Grafton said.
"It's a very hypersensitive time," he said. "But, still, common sense has to apply for something like this, and it looks like common sense just went completely out the window."
The school principal did not respond to messages.
Zero tolerance traces its philosophical roots to the "broken windows" theory of policing, which argues that if petty crime is held in check, more serious crime and disorder are prevented. So it's no accident that students are often harshly punished over relatively minor misbehavior, said Russell Skiba, a zero tolerance expert at Indiana University's Center for Evaluation and Education Policy.
"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."