From what I understand, the border is a sort of wild west in terms of citizens rights and lack there of. As usual with those seeking power and greed, boundary conditions that are not clearly defined are optimized around for their goals. Where do your rights begin and end as a US citizen? That's ignoring all the giant carve aways in your rights when it comes to reentry.
Much of it's quite silly in the era of technology and current society scales anyways where most the nonsense they could be concerned about being on your personal phone in terms of data can be conducted right inside the border without ever leaving. So the excuses for cloning phones and archiving data outside of another loophole that let's them spy on US citizens are pretty limited. Anything on your phone they could be concerned about can be archived, encrypted, and tucked away somewhere on the internet that's far less tracable. So what information do you really need? Outside of the really stupid criminals (who will eventually learn to be more sophisticated and evade these approaches), what do you expect to catch?
Much of it's quite silly in the era of technology and current society scales anyways where most the nonsense they could be concerned about being on your personal phone in terms of data can be conducted right inside the border without ever leaving. So the excuses for cloning phones and archiving data outside of another loophole that let's them spy on US citizens are pretty limited. Anything on your phone they could be concerned about can be archived, encrypted, and tucked away somewhere on the internet that's far less tracable. So what information do you really need? Outside of the really stupid criminals (who will eventually learn to be more sophisticated and evade these approaches), what do you expect to catch?
Preventing this practice should be a no brainer.