[pasbesoin]

This may be cynical of me, but: "When you're going to break the law, don't leave a physical record."

While I avoid engaging in such, I've directly observed it, and been on the receiving end -- what was done to me was illegal, but it was a 1:1 with no witnesses.

There's a useful purpose in mentioning this. Particularly for people newer and less experienced in the workforce: When co-workers and bosses won't email, IM, or otherwise write with regard to a topic. Nor address it in a group. When someone out of the blue invites you into an office, meeting room, or other private space to discuss it.

Ask yourself, "Why?"

This is one of those cases where your intuition may catch on and manifest, first. If something seems "off" about a topic or line of communication, consider it more closely.

Also works when dealing with third parties. For example, if you are dealing with a salesperson who only ever "talks" about features. Especially 1:1. Best to verify what you're being told, elsewhere, and agree to nothing until you do. (And, if you can, find someone else to deal with who's more straightforward. Not "friendly", but direct and forthright in their communications.)

[eldavido]

Sometimes I ask whether people are "Willing to put that in writing" (important verbally-negotiated deal terms).

If I get a no, that becomes part of the negotiation.