So this whole shipping detainees to sanctuary cities thing:
A) Democrats can say it's petty, and spiteful, but they can't be against it because they endlessly vouch for the well-being and goodness of the detainees. They can however demand increased funding to take care of the detainees, as they're now doing a portion of Homeland Security's job. Which in effect means Trump has to give them extra money after threatening them with pulling federal funds.
B) Trump's Administration is in a bad position, because he keeps saying there are rapists, thieves, ISIS members, etc in these groups. And he's now purposefully relocating them into areas that will make it harder to root them out and protect the country (if he's correct about the type of people coming). So the Law & Order President is actually making the country less safe just so he can be petty.
to go along with B, he's also putting a free ad out there for more to come in and get a free trip to Chicago or wherever
This is the sheer absurdity of the suggestion. He's talking about
releasing people he's been claiming are dyed-in-the-wool murders and thugs with no way to guarantee they stay within the bounds of said sanctuary cities.
Even if he is just saying this for the sake of saying, it makes absolutely zero sense if you put more than a nanosecond of thought into it. It's not even clever enough to be petty.... which I guess makes sense if it's coming from Stephen Miller.