Our venture is dealing with this very simple fact... Its not about stealing, its about loosing the rights to defend your stolen IP in the future.
If you have a valuable patentable idea, and you share details of "HOW" without an NDA then it is functional in the public domain, and no longer patentable (yes I'm over simplifying but thats the basic issue in play here).
This should be the prime consideration when deciding what you should and shouldn't disclose. If you never intend to file patents then its not as much of an issue, if you do, you are potentially destroying your opportunity for future filings.
If your not sure, then file provisionally -- this costs very little and gives you a year to follow up (but only a year, and if you don't then they are gone). This will cover the "maybe" category and will only cost a few hundred for the pease of mind.