

The use of Stingray by US law enforcement has been challenged on grounds that the law enforcement agencies have no spectrum license. Those challenges seem not to have found success.
On the other hand, prisons in the US have been stopped from operating cell phone jammers on prison grounds, on the same complaint of no spectrum license.
Encrypted data channels can still be vulnerable to man in the middle attacks. Like when you connect to an unknown host with SSH, and the client pops up a big warning.
In this case, ICE or whomever sets up a “valid” cell tower that your phone connects to, and they (law enforcement) route your packets onto the rest of the Internet. They can decrypt the 5G data, and see all of the IP headers. They can’t necessarily read the TLS traffic, such as https. But most important of all, they can log all of the IMEIs that connect, which effectively gives them a database of all of the protestors.