I'm pretty sure there's reasonable suspicion when you pull up babbling like an idiot about opting out of a simple identification check when you're driving what looks like a semi truck at a border.

He wasn't at the border. If he was, he would likely be in the wrong. This is an interior checkpoint that was set up via the Patriot Act. They can be located upwards of 100 miles from any border. The government claims they're for immigration, but they're all filled with drug sniffing dogs. This is interesting since drug checkpoints are illegal; the government can't stop you to check for general illegal activity. (It, unfortunately, can stop you without suspicion for DUI and immigration checkpoints, at least according to the Fourth Amendment hating SCOTUS.)

At any rate, there are a lot of great checkpoint refusal videos out there. They usually last 5 to 10 minutes where the agents get butthurt and go cry to their supervisors because someone won't talk to them. Unsurprisingly, most of these agents think you must answer their questions, hence the butthurt. Apparently they have zero familiarity with the Fifth Amendment.