The two foreseeable problems with it will be:
1) Activist groups crying ‘concentration camp.’
2) Flooding of the facilities to ‘Cloward & Piven’ their budgets.
This is the issue Trump held above all, so he can weather the calls of "Human Rights Violations." It's hardly going to hurt being called a racist for the millionth time, but large incarceration buildings are costly and ugly optics, and so are moms and kids in tent villages. There are things the law says Trump can do, and there are things the voters say Trump can do. I freely admit, I haven't got a clue what the voters will let Trump get away with, and where this leads in the coming months. If history is an indicator, nothing gets done and nothing changes.
The huge problem is there are not enough judges and detention space. This problem is not going to be solved by the National Guard. Pictures of them standing around yawning may defeat the purpose of this photo-op.