One thing that I think is not known by the general public is that CBP has broad authority over an area of the country that encompasses about 70% of the population. Their jurisdiction, I believe, is anywhere that is within 100 miles of a "border". I put "border" in quotes because it is defined as not just land borders and ports of entry, but the entire shoreline, including the entirety of the Great Lakes. So basically if you live in a city that isn't Pheonix, Atlanta, Denver or Dallas, CBP is there to look out for your best interest.
Nobody's ever had to care before - CBP has focused on their charter, which is protect trade and security on import and export routes. And largely, they'll never have to care again - there are 20,000 border patrol agents and we're dealing with 100 stormtroopers. 