They're doing this over the objection of state and local authorities, and despite the fact that their actions have been repeatedly ruled illegal by the courts.

Stingrays are somewhat it common practice. But they force every device to attach to look for the one they want. And its reasonable to feel queasy about that for any number of reasons.

They may not want to leave a paper trail.

“To obtain a [legal] wiretap order, law enforcement must demonstrate probable cause to a judge” [1]. Given ICE has been arresting Americans, they probably aren’t bothering with cause. Legal intercepts also require “minimization procedures to limit the interception of conversations unrelated to the investigation,” which ICE may not want to do. And perhaps most importantly, “violations of 18 U.S.C. § 2511 are considered federal felonies,” with those convicted facing criminal penalties and being subject to civil liability.

I hate to make this analogy, but it’s akin to the Gestapo’s NBH obsession. They knew they were acting illegally, and didn’t want to leave the evidence that would convict them.

[1] https://legalclarity.org/what-is-wiretapping-and-when-is-it-...

https://cellguard.seemoo.de/

It works on iOS devices without any extra hardware, even on non jailbroken devices, by analyzing baseband debug logs exported by the OS.