Not to nitpick, but it really only has been CBP and not all of DHS that has been “tested” to see how far it can go. DHS is the 2nd largest department in the federal government, and there is a wide variety of cultures w/in it. CBP is the one with the power in this case, but just because they’re going along with this EO doesn’t mean other parts of DHS are on board. That still remains to be seen. Trump & Co knew CBP would be the path of least resistance since its union backed Trump. It was a pretty safe move on Bannon’s part.
Of course the question now is will there be any repercussions for the CBP officers who ignored the courts’ orders?