How can this be stopped, from a technical perspective? Can I wrap the comms in a Faraday cage? Obviously it would be better to have this action be illegal. But with legal privacy protections eroding in the US and other countries, it seems prudent to have a better understanding of the systems involved in the immoral surveillance.
It can't. Not realistically.
It can be stopped by legislation. But that would require politicians who have our interests as a priority rather than the various industries. So not going to happen anytime soon.