We are a small marketing consulting company. Usually we are invited to solve some kind of problem or task. But we face a large problem. Our offer needs to have an idea of how to solve a particular problem. Of course we do not write everything, but the main point is supposed to be supplied. The idea is usually the reason for hiring us. It happens and quite often, that our project is not accepted but after we just realize that that our ideas and solutions has been stolen.
I know that NDA should be the solution. But it is not easy to prove that they did not developed the same idea just a couple of days ago the presentation.
Have you any idea how to protect against this?