Zero tolerance may be the order of the day in an increasing number of schools, but the critics who call the policies ineffective are getting louder, saying too many good students are being punished because of a few bad ones.

Many schools today use metal detectors to search students for weapons. Others go further, providing constant police presence. But how much of a danger are your kids really facing?

"I've never found a weapon on a student," said Calvin Land, assistant principal at Foshay Learning Center.

And in eight years, neither has the entire Los Angeles school district. In fact, a child is more likely to get struck by lightening than to die in a school shooting.

"Last year, you had a one in three million chance of dying in a school," said Jason Ziedenberg of the Center on Juvenile and Criminal Justice.

And despite incidents like those at Columbine and Santana high schools, the odds are getting even lower.

In 1993, there were 55 violent school deaths. In 1999, there were 30 — half of those at Columbine. And in 2000, there were 16.

But children aren't feeling any safer. Students in schools with tighter security are actually more afraid of violence than students at less restrictive schools, according to a University of Maryland study.

Still, some educators insist that schools need to be tough on violence as soon as it emerges, no matter how benign.

Arnold Goldstein, who heads Syracuse University's Center for Research on Aggression, has counseled a zero-tolerance policy: discipline students with detentions and suspensions.

"Even the low-level stuff of bullying, cursing, if it's ignored, it's likely to escalate," he said. "Kids have to learn behavior has consequences."

But — like zero tolerance — tough and well-intended policies meant to protect children may also make them more vulnerable. Recent examples include a child who was suspended for drawing a picture of a soldier, and a National Merit Scholar who was sent to jail for having a kitchen knife in her car.

"I think that problems lie a lot with bureaucracies," said John Lott of the Yale University Law School. "[Bureaucracies] adopt rules that don't really think through the consequences."

The Associated Press contributed to this report