Americans want foreigners to go home.
Fine, incarcerate them with with the parents, then deport them with the parents
Un-American it might be. But the border-crashers are, for the most part, un-American too.
In a surprising number of instances, these are not even real families, but an adult who has swept up several perhaps otherwise unrelated children, and then claim “refugee” status, for the children, of course. Separate the children from the persons who claim to be their parents, and watch the reactions of both the children and the attempted border jumpers. If the children show great relief, or if the parents appear to be largely not concerned, that is a pretty serious tell regarding their intentions.