Interesting. Eight years ago I worked as a buyer for the aggregator with the largest criminal database and I don't remember having to sign an NDA during those sorts of talks. It's possible I've forgotten, but I think it was more a matter of people wanting to know our coverage as much as we wanted to know theirs.
As an aside, the value of those talks wasn't usually in acquiring the data, except maybe in the short term. We always preferred to go directly to the source. The value was simply in learning that the data from a specific source was even available. In a few instances, that got pretty frustrating, since I knew that the seller of the data was scraping a given court's website against that court's wishes (and the TOS on the website), with all associated problems with accuracy and ethics that entails.
Those are provable damages, and maybe slander if they can convince the court they're a publication
Another reason to be NDAed up.
Just having that conversation required getting a mutual NDA in place, since the conversation involves revealing your capabilities (even if not your sources). And that's assuming you're even aware of all the NDAs your company has signed with other companies, which isn't always the case. Speculation or name dropping in public could violate an NDA you're not even aware of, then you find yourself having to defend your speculation as just that, rather than as revealing proprietary knowledge (that you didn't actually have but your company did).
At the end of the day, it's easier to default to speaking in generalizations rather than risk the potential repercussions of not doing that. :-/