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"?
Take the advice offered by journalists on how to contact them privately and avoid getting caught. I.e. secure and protect evidence without raising suspicion. Contact a reputable journalist via some secure means of communication. Let them take over and keep silent. Don't brag or something.
Most good newspapers offer something like PGP encrypted mail, SecureDrop over TOR and more to talk to them.
Absolutely. There are many reasons, but attacks on journalists/whistleblowers and the malicious potential of collated data in a capitalist oligarchy are the first two that come to mind.
Encrypt email with anyone who publishes a key. If "bad" emails are the only ones you encrypt, then that metadata can be used to raise suspicion of you and to trace your contacts.