Some people sometimes have really good ideas and an understanding of some niche market that I, the programmer, had no idea even existed. But those are domain sp

Some people sometimes have really good ideas and an understanding of some niche market that I, the programmer, had no idea even existed. But those are domain specialists and not "idea guys" (and gals). But the question is, if you are not a domain specialist, how do you distinguish between the two? And how do you evaluate whether the domain specialist will be a good business partner and not just drop work on you? It's quite simple really. The way I do is that I am available to have a coffee with anyone who says has an idea and talk about it. There's not much to loose there, it's networking. After being presented the idea, I instruct the person to do the legwork that follows, be it market research, interface design using paper or the marvel app or similar, testing the idea with potential users, analysing the competition, juridic analysis, and whatever else business related work that is necessary but I have no interest in doing. What happens everytime without fail is that if you are dealing with an "idea guy/gal", they will bail on the first task and never get back to you. There you have it, a simple screening process that will spare you the trouble and filter out the useless business partners.