An incident this week in Clinton County demonstrates how efficiently social media can spread information — regardless of whether the information is true, false or just misleading.

Officials with the Keystone Central School District said authorities sent a flyer to principals warning them about a man who police said could potentially pose a threat to schools. State police arrested a man for DUI a few weeks ago in Lycoming County, according to the flyer. During the arrest, the man made references to mass shooters.

Such information exchanges are routine these days. In the wake of the 1999 Columbine High School massacre in Colorado, and several mass shootings since, alert school and law enforcement officials adhere to a better-safe-than-sorry policy — even when, as in this case, for example — there’s no imminent threat to schools or children.

But somehow this routine exchange of information went awry. The flyer, intended only for principals, made it onto social media sites Monday and spread like wildfire. Many parents, fearing some sort of attack, kept their children home Monday morning; others pulled their children out of school as the alert spread.

Classrooms at the Central Mountain High School were nearly deserted within hours Monday, according to news accounts. “There was a lot of people missing,” one student told a TV news reporter. “There were only four people in my homeroom class today.”

Later Monday, the district released a statement saying these kinds of alerts are common in an effort to be proactive and keep the schools safe. “There was never a direct or imminent threat to our schools,” a school official said, “and had there been, officials would have acted accordingly.”

It’s difficult to say parents overreacted. Who can blame them for protecting their children?

It’s equally difficult to find fault with social media. After all, who would question the veracity of a flyer sent by law enforcement to local school administrators? And Columbine, Virginia Tech, Sandy Hook Elementary in Connecticut and other mass shootings have taught us the need to respond without hesitation in the face of violence — without expectation of a second chance.

The incident suggests it’s time for school districts to conduct lockdown/evacuation drills as routinely as they do fire drills. A few area districts already have a lockdown drill, says Sheriff Mike Slupe. He says it might be good policy for every district to conduct an annual lockdown drill.

“Every school has fire drills,” Slupe says, “but I can’t remember the last time a kid died in a school fire. But the shootings we read about all the time. A drill might save lives.”

A lockdown drill would be more detailed and more time-consuming than a fire drill and would require extensive planning. It might entail two or three rehearsals in one day.

The drill should involve the participation of emergency response and law enforcement personnel as well as parents. The drill could be a one-day event, incorporated into school orientation exercises at the beginning of the school year.

There also might be a “stand-down” element to prevent overreaction like the one experienced this week in Clinton County.

For better or worse, routine violence alerts are a modern-day reality that suggest we should prepare for the unthinkable. A routine drill can and should be part of our preparation, not only to improve and accelerate an emergency response, but also to stop a response when the perceived threat was unfounded.