Hypothetically, if you are a witness or whistleblower who's adversary was a very big corporation (such as boeing), what measures could you take to prevent yourself from being "suicided"?
With whistleblower information, why hold it back in the first place? Wouldn't it be better to release it immediately if they might kill you either way?
IIRC the problem there is that it potentially makes you liable to be sued by the company for disclosing negative/private information. But they can't exactly hold you liable if you're dead, so if you're dead you may as well speak what you know from beyond the grave.
Additionally, give a copy of all the documents to your lawyer to release in the case of your death. Multiple Deadman switches are better than one, especially one that's controlled by a person and not just hoping your cloud service doesn't go down after you're dead.