President Trump certainly shouldn't have deputized CBP tactical teams to do internal law enforcement tasks inside cities, but it's worth pointing out that CBP's authority to conduct routine law enforcement under the same authority as, say, a local police officer is a much grayer area than this "100 mile Constitution free zone" stuff. CBP shouldn't be grabbing rioters or protesters or activists off the street at all, obviously, but if they're doing it based on the same probable cause a local police officer would be using for the same stop, they're not implicating the border search exception.