Actually the Imagineers use it quite a bit. I've watched several documentaries where Imagineers are talking about rides and development and mention their "Blue Sky Meetings." Also, if you buy any of the books written BY the Imagineers (some of the ones I've read lately are the "Imagineering Field Guides to...") they use the term. In the field guides they even have a glossary of "Imagineering Lingo," for people who don't know the terms (keep in mind this is a book WRITTEN by the Imagineers and is credited as such), they define Blue Sky as:
Blue Sky - The early stages in the idea-generation process when anything is possible. There are not yet any considerations taken into account that might rein in the creative process. At this point, the sky's the limit.
They also have a definition for Brainstorm which goes into the process of how they go about it. Here's their "Brainstorming rules."
Rule 1 - There is no such thing as a bad idea. We never know how one idea (however far-fetched) might lead into another one that is exactly right
Rule 2 - We don't talk yet about why not. There will be plenty of time for realities later, so we don't want them to get in the way of the good ideas now.
Rule 3 - Nothing should stifle the flow of ideas. No buts, or can'ts or other "stopping" words. We want to hear words such as "and," "or," and "what if ?"
Rule 4 - There is no such thing as a bad idea. (We take that one very seriously.)
All this is quoted from the book.
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