One -- in Los Angeles -- decides to call off school, with the superintendent saying students won't go back until he's absolutely sure everything is safe.
The other -- in New York -- decides just the opposite, dismissing the threat as an apparent "hoax."
There's no easy answer. It depends partly on timing, given that Los Angeles authorities acted just before classes began on Tuesday, while the New Yorkers' comments didn't come until midday. And location matters: Los Angeles is just 60 miles from San Bernardino, where 14 people died about two weeks ago in what authorities called a terrorist attack.
So, too, does the perspective of individual students and parents -- some of whom might think calling off class is an overreaction, while others think doing anything other than that would be irresponsible.
David Katz, a former special agent for the Drug Enforcement Agency, told CNN that New York made the right call and Ramon Cortines, the Los Angeles Unified School District Superintendent, made "a big mistake."
"You do not under any circumstance take action unless the threat is corroborated," Katz said. "For example, if a high-rise office building gets a bomb threat in New York City, the police department is not going to come over and evacuate your building absent some credible information."
Katz said Cortines should not have been the one to make the decision to shut down schools.
"You need somebody with a little background in this area to make that determination, to say this threat warrants closing the school system," Katz said. "This one just warrants an absolute increase in security and police presence, of course, but not the disruption of the entire school day for that many children. It's just not the right move to make."
L.A. superintendent: I won't 'take the chance'
While New Yorkers started their school day earlier, the first word of anything awry came from Southern California about 7:15 a.m. PT (10:15 a.m. ET). By that time, classes hadn't started yet, though some schools were already opened.
A school official received an "electronic threat" earlier that morning, a message that referenced many, unnamed schools and "talked about backpacks (and) other packages," Cortines said.
School district spokeswoman Shannon Haber said an email sent overnight directly to a school board member had originated in Frankfurt, Germany. But LAPD Chief Charlie Beck said later the original email was routed through Germany and its origin has yet to be determined, but it's thought to be much closer than Germany.
Cortines noted that his school district, which is the country's second largest with about 650,000 K-12 students, gets threats all the time. But, addressing reporters alongside the head of his school district's police department and an official from the Los Angeles police, Cortines described this latest one as "rare" -- in part because of what's happened recently in San Bernardino and internationally.
"I, as superintendent, am not going to take the chance with the life of students," he said.
New York: 'Huge disservice' to call off school
A superintendent in New York's school system got an email "almost exactly the same as received in ... Los Angeles," New York police Commissioner Bill Bratton said.
But in America's biggest school district, nearly 1.1 million students weren't sent home. That's because authorities looking at the same information believe it is a "hoax," said the commissioner.
"We've come to the conclusion that we must continue to keep our school system open," Mayor Bill de Blasio said. "(It is) very important not to overreact to situations like this."
Those comments, and Bratton's remarks, seem to suggest that New York authorities believe that's exactly what happened in Los Angeles.
The New York mayor characterized the email threat as "so generic (and) so outlandish."
"There were wording choices and other indicators that suggested a hoax and not anything we could associate with jihadist activity," de Blasio said. "So (we decided) it would be a huge disservice to our nation to close down our school system."
L.A. police chief: 'Irresponsible' to criticize cancellation
Not all law enforcement authorities agree that canceling school in the face of this threat was the wrong call. Just ask Chief Charlie Beck of the LAPD.
His department learned "very late" Monday night that "a very specific threat ... had been delivered via email to a number of people on the school board. After reviewing that threat," Beck said, "we became very concerned."
His officers, working with federal authorities, instantly began investigating whether the message was valid.
It was ultimately up to Cortines to decide whether or not school should be in session. But -- like Mayor Eric Garcetti -- Beck said he supported the school district superintendent's choice.
The police chief pointedly challenged dissenters, saying it is "very easy to criticize a decision based on results that the decider could never have known (and) when you have no responsibility for the outcome of that decision."
Beck alluded to the tense atmosphere in the region since the San Bernardino carnage, plus Cortines' daunting responsibility of keeping about three quarters of a million students and school staffers safe day in and day out.
"I think it's irresponsible based on facts that have yet to be determined to criticize that decision at this point," the chief said.
"These are tough times ... Southern California has been through a lot in the recent weeks. Should we risk putting our children through the same?"