Should I insist on an NDA?
Would you lend someone your car without it being insured?
Why would you then share your confidential information, secret sauce, how you achieve competitive advantage etc. all resting on the hope that the receiver of that information will not take it elsewhere?
They may not even share it deliberately, they may do it without thinking.
By insisting on an NDA you will draw attention to the fact that you value your intellectual property and are careful about how you share it around. This is actually an important part of your defence and it will also make investors look more carefully at your intellectual property.
Also worth pushing the other party to understand why they will not sign an NDA. What you want to hear is how they carefully ‘Chinese wall’ information, train employees and have strict policies against sharing secrets.
You should be taking a calculated Risk (my secrets will be misappropriated) vs. Value (benefit from working with this party) calculation, because even with an NDA you are still at risk.
The process of thinking about and protecting your intellectual property will also lead to you categorise your confidential information into categories (top secret, secret and confidential). Having done this you will be more conscious about what you share, with whom and under what conditions.
Having done this categorisation, even if you end up not signing an NDA then you will be conscious about retaining crucial confidential information and not sharing it. For example you might describe what effect a confidential trade secret might have on value but not actually reveal what the secret is.
Why allow someone do a drive by and steal your secrets?