Under the policy, up to 24,000 Venezuelans may apply for humanitarian entry into the United States by air.
U.S. officials told Reuters that 300 had been expelled border-wide from the United States the day before.
Ramirez said her husband was allowed to stay in the United States while she was sent back on Thursday, a move she called "inexplicable."
Those trekking over land toward the United States have an arduous route through Central America and then into Mexico.
The U.S. Department of Homeland Security (DHS) did not immediately respond to questions about the separated Venezuelans.