Pretending I don't have Fourth Amendment rights on one side of the Customs desk at said ports of entry is not.
As for coastal areas, though, If CBP can stop me away from the border without a warrant and without reasonable suspicion of a crime, that IMO is a Fourth Amendment violation. The ACLU cites specific cases of this happening: https://www.aclu.org/sites/default/files/field_document/14_9...
> Between 2006 and 2010 in the Rochester, NY, area, approximately 300 immigrants with legal status were arrested by Border Patrol agents, then released
They also cite the regulations establishing the 100 mile rule: https://www.law.cornell.edu/cfr/text/8/287.1 defines "reasonable distance" and "external boundary", and https://www.law.cornell.edu/uscode/text/8/1357 utilizes those definitions to do things like "without warrant... interrogate any alien or person believed to be an alien as to his right to be or to remain in the United States" and "to board and search for aliens... any railway car, aircraft, conveyance, or vehicle".
It's quite clear that significant parts (all?) of Delaware fall within that claimed jurisdiction.
I guess we could go back to 1910 and only import stuff and admit people in coastal cities. Make everyone from Europe fly to JFK on the way to Atlanta.