Just went through a Border Patrol checkpoint yesterday. It is situated thirty miles from the border at a chokepoint that is better observed and supervised than anything closer. The Patrolmen were going through a car and had the tire off. The patroldogs or sensors had picked up something. The day before they discovered 10 kilos of heroin. Just another day at the office.
Maybe they can actually make a case out of that, if the checkpoint you are referring to isn't in New Hampshire, or the federal agents file federal charges.
Under the NH Constitution judges have found that drug evidence found at Border Patrol checkpoints was illegally obtained, and cannot be used in state courts.
There is nothing wrong with checkpoints in appropriate locations. I've seen them working very effectively in California. But in New England if you want to catch illegal aliens you head for where they are. And that isn't along the road in northern New Hampshire.