If you don't know where you're going, any path will get you there. Missions are useful things but they are just words. What is critical is not the word on the page but the process of development which gets the executives at the top into some agreement and alignment and which transfers ownership of the end result to the front-line workers. It will be mostly their own, but influenced by the others. Then they have 5 minutes to run around and ask anyone from another table about their ideas.
Questions can be of any subject.
It was a fast-paced, highly interactive session where we got 20 sets of 4 to 5 opinions total. But the majority of people stayed because of their shared involvement with their and the other teams. Facilitation and Processing this development process. I use the Fast Networks framework to get every member of each tabletop Mission Statement Development Team to interact with at least 3 other people not on their team for their thoughts and ideas about the mission and about key phrases or words that should appear. Quality is less important at this stage than impressions and initial thoughts of the team.