All but three of the nine students still stuck in their home countries are Middle Eastern, Ladd said. The remaining students are from China—which probably results from a regulation predating the terrorist attacks of Sept. 11.

Ladd and her associates have been coaching international students on how to avoid getting caught in a delay. Much of the HIO’s efforts have focused on the immigrant-intent issue.

“We’ve tried to give people more guidance on how to overcome this presumption,” Ladd said.

But even with an eye to guidance, the HIO’s coverage of student concerns hasn’t been perfect—leading, in some cases, to further complications. Rowan W. Dorin ’07 realized shortly before coming to Cambridge that his visa forms lacked an important signature from the HIO. In the past, he said, the office had reported missing components of his applications significantly ahead of time. When Dorin reported the omission, the HIO told him that there was nothing he could do—except to plead for an exception with the customs officer.

“Having gone through American customs before, I thought my chances of their not noticing were next to none,” Dorin said. He pleaded and, to his surprise, he said, the customs officer let him through.

But Dorin said it was an experience he hopes not to repeat.

“It’s clearly my fault, because the HIO is so good ordinarily,” he said. “If anything, they lulled us into a false sense of security.”

—Staff writer Nathan J. Heller can be reached at heller@fas.harvard.edu.