The bomb threats phoned in to several Berkshire schools are apparently part of a Massachusetts epidemic. They pose a real dilemma for school officials.

The Boston Globe reports that 12 schools received bomb threats on Tuesday, which followed nine threats reported on Friday, the last day of school before the Martin Luther King Jr. three-day holiday weekend. New Hampshire and New Jersey report a similar outbreak.

Many of the calls were computer-generated, similar to the irritating messages of political candidates, and were generally dismissed as invalid. Arlington, however, closed its high school when the automated call threatened not only a bomb detonation but the gunning down of students as they fled the building. Given the prevalence of school shootings in the United States, the latter threat had to be considered extremely seriously.

The problem with closing schools, of course, is that doing so "rewards threatening behavior and encourages more threats," in the words of a Twitter message posted by Billerica school officials after they decided not to evacuate district schools after a phoned in threat.

Obviously, no school officials want to be second-guessed, but in general the ideal response is a quick sweep of the building by State Police or other appropriate officials. Closing schools does reward and encourage cowardly get-a-lifers and fuels the ongoing threat epidemic.