I think this is something where the perception of utility is far different in the startup world that big enterprise. In the enterprise world, where there are too many people with too many complex business relationships to keep track of everything, and too diverse a group of meeting participants to know everything about them, and where you may not be discussing your IP or your business deals but the situations of your own customers or suppliers, an NDA is a no-brainer. It amounts to much the same thing as doctor/patient or attorney/client confidentiality principles and allows free, assumed-secure speech in any environment where all parties present may not otherwise have an appropriate level of trust to be comfortable engaging that way. In my business of contract engineering & manufacturing, we don't create nearly as much internal IP as we handle the IP of our customers. However, we apply our unique processes & systems to achieve the goals of our customers and if we want to discuss how we do that when engaging with potential new customers, we absolutely require NDAs. It doesn't help things that in the EMS industry almost all the big OEMs have contracts with several competing EMS companies (just look at Apple with Foxconn, Samsung and Pegatron, for example... or Dell/HP using both Quanta & Compal... but also using Flextronics, Sanmina, Jabil and Celestica.). It gets messy fast and ensuring legal recourse for accidental or intentional leaks is a necessity.
On the other hand, as an established business, if you needed the sort of consultation this guy is providing for free to would-be startups, you'd pay for it. Not only does this drastically change the risk/reward tradeoffs for the consultant, your issues are likely to be a lot more concrete and specific than pie-in-the-sky I've got a revolutionary idea startup stuff.
