Just before the Maryland School Assessment tests were given this year, Baltimore schools chief Andres Alonso recorded an unusual eight-minute video with a special message for administrators and teachers.

Maryland state investigators had found unusual numbers of wrong-to-right erasures at some city schools in previous years. This happened in the District too, but unlike D.C. school leaders, Alonso warned of severe consequences from any tampering with the exams.

“If there is anybody who is thinking of any kind of irregularities, I need you to understand that your entire professional livelihood is on the line,” he said. “We are not talking about termination. We are not talking about being transferred. We are talking about losing your professional license.”

Last year Alonso, the chief executive officer of Baltimore schools, had the teaching license of a principal revoked because of erasures at her school. At a June 23 news conference he went even further, announcing that cheating had occurred at two other schools. Next to him was Maryland Superintendent of Schools Nancy S. Grasmick, who said those involved in tampering could lose their professional licenses. (Grasmick retired last week.)

Testing experts say large numbers of wrong-to-right erasures are signs of potential cheating, since children rarely make such corrections themselves. Indications that answers may have been changed after students went home have popped up in the District and several states, with many school officials moving slowly and reluctantly to address the issue.

Alonso has been an exception. When the principal last year lost her teaching license, Alonso said it made no difference that she denied knowing about the cheating. As the principal, Alonso said, she should have known.

D.C. Public Schools Chancellor Kaya Henderson has not said anything like that. The response from her and the D.C. education agency responsible for testing has been to beef up security, ask the D.C. inspector general to examine a consultant’s report that found little wrongdoing and express confidence in the ethics of D.C. educators.

I have heard no one at school headquarters threaten anyone with losing a license. Maybe it’s impolitic to do that. But it would send the message that school supervisors better get on top of this, now.

(I should disclose that my wife, Linda Mathews, recently edited a series for USA Today that put a spotlight on possible tampering with standardized tests in the District and elsewhere.)

Jonathan Inskeep, a former Baltimore teacher, said little was done when he complained of cheating on state tests in 1995. Union officials told him he had done the right thing and they would protect him. “But they also said they would protect the teachers who were cheating,” he told me. Eventually, the principal involved was transferred to a central office job and the teachers involved were suspended for a month without pay, Inskeep said.

According to the Baltimore Sun, the president of the Baltimore schools administrators’ union is complaining about Alonso’s insistence that principals bear responsibility for cheating even if they weren’t involved.

Alonso told me that when the signs of cheating were unmistakable, he had to act against the school leader because “a principal should have known the kids” — and therefore known something was wrong.

I asked if the school system’s lawyers were advising him to be cautious.

“Sometimes I don’t care what my lawyers tell me,” he said. When the number of wrong-to-right erasures becomes overwhelming, he said, “there has to be a very tough conversation with the principal.”

If D.C. school leaders leapt on the erasure issue as quickly as Alonso and Grasmick did in Baltimore, some principals probably would have lost their licenses already. But in this tale of two cities, one school system has decided to take cheating very seriously and the other, at least based on public statements, so far has not.