Kamala Harris, citing seemingly classified intelligence, famously raised the alarm on Bluetooth earphones to Stephen Colbert:
“I know I've been teased about this, but I like these kinds of earpods that have the thing [pointing to the wire] because I served on the Senate Intelligence Committee. I have been in classified briefings, and I'm telling you, don't be on the train using your earpods thinking somebody can't listen to your conversation.”
I doubt this was ever classified information. It's written all over DoD and NSA requirements and best practices for staff and diplomats.
She was probably briefed repeatedly about this as a member of that committee.
Here's one example:
> Headphones are wired headphones (i.e. not wireless) which can be plugged into a computing device to listen to audio media (e.g. music, Defense Collaboration Services, etc.).[0]
“I know I've been teased about this, but I like these kinds of earpods that have the thing [pointing to the wire] because I served on the Senate Intelligence Committee. I have been in classified briefings, and I'm telling you, don't be on the train using your earpods thinking somebody can't listen to your conversation.”
https://www.aol.com/kamala-harris-warns-against-wireless-150...