Thinking about people writing inappropriate emails.
IANAL but in my professional life, I helped sort out various messes, client service failures and staff matters. Not my official role but used as a black hat (prepared to be disliked as I sorted stuff and kept lawsuits to a minimum).
The first instruction - preserve all documents, notes, email, electronic files.
Second instruction - do not create any new documents, emails, explanations, slack conversations, online chats, etc until given detailed explicit instructions on how to do so that it was covered by privilege (attorney work product).
Third instruction - do not discuss among yourselves
Depending on where the problem was happening - If 2 or 3 was not respected, I was known to appear in the offenders office and explain consequences, including that people with broken fingers struggled to type. If not, a scary phone call and a reminder of the instructions.