https://www.citylab.com/equity/2018/05/who-lives-in-border-p...
Even though it has a trivial workaround of not looking the part. The Lod Airport Massacre "terrorism swap" with Japanese Red Army Terrorists and Popular Front for the Liberation of Palestine-External Operations in 1972 shows just how useless it is as a measure.
It's just so dumb, and I've heard a lot of older people especially who will say the common "Why is it a problem if you've got nothing to hide?". I think some people fail to understand the kind of data people can have stored, and how much of some people's lives are part of their digital devices. I'm sure they wouldn't want police coming into their house and searching it.
They can't extend the traffic stop to bring in the dogs unless they have reasonable suspicion. https://en.wikipedia.org/wiki/Rodriguez_v._United_States