In a child’s concentration camp (a.k.a. “baby jail”) switch the children’s coloring paper for blank signed release orders.
Have everyone crossing the border dress as a CBP agent. When encountering real CBP agents, accuse them of being impostors and demand to see their paperwork.
Offer a celebration in ICE/CBP’s honor. When the agents arrive, deport them to a random country.
Slowly move the border fence, inch by inch, until Mexico recaptures all of its former territory.