Sure, that's why I said "Plan for the worst, hope for the best". It's always possible, even if mtg with an ethical company, the junior person you're meeting with that day could be a new-hire who's an idiot and tries to get actionable information.

NDAs aren't deterrents. At the same time, any secret that can be casually conveyed in a mtg, typically isn't all that valuable. If you have a strategic investor as an outside board member, a smart founder will ensure nothing disclosed in a board mtg or board materials is specific enough to be competitively actionable. If you do it correctly, they shouldn't gain any non-public info more specific than broad sales growth, and there are a lot of completely legal ways for interested Big Co competitors to get good intel on sales growth which are much cheaper and easier than investing.

That's why we generally passed on even evaluating most startup investments. They just weren't worth the time to manage plus if we really planned to be active in that space the legal exposure would require a formal "Chinese Wall" between our investment and our business unit, usually managed and audited by an outside law firm. If we were truly interested in the space, I'd always argue we should just acquire the startup now, buy one of their competitors or tilt up our own 'build it' version.