The biggest disadvantage of NDA’s, I believe, is jurisdiction. While multilateral patent agreements exist across many first-world countries, such is not the case for NDA’s. This allows NDA signers with particularly valuable intellectual property to move to a different country and sell their stolen ideas.

NDA’s, as mentioned above, are of course extremely useful for protecting IP that is not easily patentable or protectable by other means. One particularly important use for NDA’s is when it comes to trade secrets. A company with incredibly valuable IP – such as SpaceX with its rocket blueprints – will not publish patents and instead will have trade secrets. Trusting the right people and using NDA’s is a better strategy here because other countries will, of course, prioritize national interests over patent law.

This is just one exception to the norm of patenting one’s IP. Many others exist; do any of you have any examples that you are aware of?