There should be no detention and they should certainly not be let loose.
You are caught - then you are given 30 strokes with a cane and put on the next bus to Mexico or wherever - and put on a list to never be given a visa to the US.
No applications for amnesty should be accepted at the border - consulates and embassies only.
No citizenship for merely being born in the US.
I completely empathize with desperate people trying to make a better life. But we must have the rule of law and the entire world cannot live here. Fix your own countries.
Well said.