Ok, I re-read my comment and it might sound a tad creepy...  But I assure you this is already done all over the US now such as at state and county lines, and even when going from one agricultural area to another (to prevent the spread of agricultural pests), not to mention along the border areas and some north-south routes where trafficking is known to happen. It is well within the rights of law enforcement to stop us most anywhere for various and sundry reasons.

Is it a pain in the tukkus?  Yes, it can be.  But you plan for and allow time for it just like we do for crossing the bridge or the ferries.  The point is that we are in a unique area where this would actually work and work well.

A bonus is that the need for additional manpower would create some of the jobs that we need, too.  And not junk minimum-wage jobs.  Good paying state or federal jobs with actual benefits that mean something.