PaulGT3:
The NDA is a business instrument, essentially, and somebody put up some seriosu money to cover the research costs, and thus wants to have some measure of control of that information the money paid to learn. It's just a comment on the modern world where research need sprivate funding and the private funding wants some control to potentially recover the investment by a TV program or DVD sale or book release that discloses the info the investment paid for.
Lacking the NDA's the info could be released in ways that undermine the prospect of recovering the investment.
Bottom line, the NDA thing is a money/business issue.
Bill