I did help desk support at a news agency. We were constantly cleaning up malware from journalists computers... The journalists were constantly downloading all sorts of sketchy files as part of their job. Basically, if you're leaking state secrets / embarrassing repressive governments, don't leave a digital trail that can be traced back to you. Just assume everyone (especially journalists on national security or human rights beats) have been hacked.
Yes! In our newsroom (which isn't perfect by any means) - I have been testing using Qubes for really sensitive/untrusted documents. We also open un-trusted documents (from e.g. FOIA responses) on a machine live-booting from a CD.
However, it adds enough friction (especially with remote work) that it's hard to get it right 100% of the time.
If you want to share really sensitive documents, one way to ensure proper handling of your documents is to use a service like SecureDrop [0] which for e.g. only accepts submissions over Tor and requires the use of a secure viewing station [1] (air-gapped machine live-booting Tails w coreboot rom + webcam/networking card physically removed) to decrypt/access leaks.
That being said, I don't think there's a perfect tech-only solution because nothing is stopping folks handling it carelessly after they access the file.
You could also use Dangerzone [0]. It opens a document in two docker containers and converts it into a safe version. It was created by the director of infosec at The Intercept.
