Understanding what an exit plan is and when you would use is important. With that said I don't believe in focussing on exit plans for start-ups, and certainly not as a key question during the formation process.

They distract from core mission: which should be trying to build great products, a great service, or have a great impact on our world. Focus on building something lasting and meaningful. If you do that, the exit will be their when you need it, but hey, build something great, and maybe you won't want to!

*(Rusty is right that this is the second question founders are asked, but it's a lot more fun to tell an investor "I don't have an exit plan" and watch their face, than say the so cliche "Acquisition, IPO, merger, etc". Plus, they make cool facial expressions when you do this!)