It's not a folk truth that I saw it, in a mainstream news report, said by a Border Patrol employee to justify their actions more than 100 miles from the border. That's not a misinterpretation; that really happened. At least once.
I would be delighted for it to not have been an actual administration claim, ever.
Fair, I have no doubt that someone has falsely claimed it in order to do an illegal search, but it still is a false claim and (based on current understanding of the law) would not hold up in court.
As it is the 100 mile zone sweeps in most of the population.