One of my concerns when I look at ideas to license from the inventor is how many people they have disclosed their idea to. When they tell me they've showed it to their family and friends and everyone in between and everyone thought it was the greatest idea and will make millions, leads me to believe that they have been pretty loose with their disclosure. That concerns me.
So when someone tells me they have kept it fairly tight and anyone they have shown it to has signed a Non-Disclosure / Non- Compete Agreement, this leads me to believe that they have been very protective of their idea. This is the response I like.
Asking someone to sign a Non-Disclose / Non-Compete Agreement is a common practice. It lets the party know that you take disclosing your idea to them very important and as such by signing a document, it heightens the awareness that they should also.
Although many manufactures especially those with other similar products will refuse to sign on the premise that they may have something like it in the pipeline. This may apply to angels and VC's as well, as most are familiar with what their investments are working on.
I never get offended when asked to do so, in fact, I always prefer to. My stance has always been, if they refuse to sign, I move on.
Best of success to you.