“Why good design comes from bad design”, by Scott Berkun is an excellent article on a very overlooked point.
Why showing how you got your design, and how you got there, will help you out.
By keeping a log of your design process, bad ideas, stupid ideas, etc, you will be able to show the thought and effort that went into creating the design that you will eventually have to present. And it will help slow down, maybe even stop, the barrage of suggestions, ideas and criticisms about your design. By showing bad ideas, you show that you've spent time on this. And have worked out problems that they might not have even realized.
It's one thing to tell people you've gone through this process. It's quite another to show them with sketches.