A.C.L.U. lawyers said they were concerned that deportations could happen so rapidly after reunification that migrant families might not have enough time to understand their legal rights and might give up their right to pursue a petition for asylum.

The advocates were reacting, in part, to the stories of people like Celia Del Carmen Delgado, who said she initially agreed to deportation because an Immigration and Customs Enforcement agent in Texas told her that if she did, she would be reunited with her 3-year-old daughter, Adela. Ms. Delgado said she never spoke with a lawyer before she made the decision. But even after she agreed, her daughter was not immediately returned, she said. “When the moment came,” she said, “it was just me, and I said, ‘No.’”

When she was told she would be deported without her child, Ms. Delgado said, her whole body began to shake, and she had to be restrained by force. She said other mothers around her were fainting.

Some parents appeared to have been so overcome with anguish after being separated from their children that they were not sure what they had agreed to in order to get them back. Two fathers in New York originally told their lawyer, Mario Russell of Catholic Charities, that they had accepted deportation orders while they were in custody as a condition for the recovery of their children. But after their families were reunited, the fathers said they were unsure. Mr. Russell was trying to clarify with the government.

The one-week stay in deportations ordered by Judge Sabraw came as the government was preparing to carry out large numbers of reunifications in the coming weeks, facing a July 26 deadline imposed by the judge for returning all eligible separated children to their parents. The government plans to transport up to 200 children a day in order to reunify them, according to a detailed plan filed last week.