Also curious about this, "wild" is not a word I would have used for the checkpoints they set up. They've been doing it for nearly 40 years and yet our civil liberties are still intact.
As an observer of the process, they definitely have an impact. You can see people spot the checkpoint and then peel off to the nearest onramp / off-street where they then get picked up by the special checkpoint designed to ask some questions of people willing to cross medians to avoid a standard checkpoint.