We do know of shady companies that sell "own this phone" USB devices to governments, but AFAIK they only sell to governments and the details aren't available to the public.
I have never heard about a non-government sponsored attacker doing that kind of thing. If this is relevant or not to you, it's a matter of your threat model. If I were a journalist, I would be very weary. Personally, I don't plug my phone on random outlets and don't plug random devices on my computers, but it's clearly an overreaction.
Heh, if I'm remembering right, a couple of years ago there was a public charging station at DEFCON that was sponsored by the NSA. I did not plug my phone into it :D
I have never heard about a non-government sponsored attacker doing that kind of thing. If this is relevant or not to you, it's a matter of your threat model. If I were a journalist, I would be very weary. Personally, I don't plug my phone on random outlets and don't plug random devices on my computers, but it's clearly an overreaction.