When something goes wrong on a large scale in your company, you need a plan to talk about it quickly and effectively. It might seem like communication is just something that should happen naturally. So why would you need best practices for talking about something?
Think about all the channels you can use to communicate, how much data can get lost along the way, all the different groups that need to be looped into the conversation, and the different pieces of information each of those groups need. What tools are you going to use to keep track of decisions the responders make? What do your internal stakeholders need to know? How are you going to loop in customers, and how often?