I had a guy on another forum asking about detecting movement in a video capture from a camera where the camera was subject to moving around because it was mounted on an outside pole.I knew the solution because I had solved the same problem and my company had take out a patent on the solution, all I said was I knew how to solve the problem if he wanted to pay my company lots of money they could supply him with the code or he could think about the problem with a couple of hints, in the end he came up with some ideas of his own avoided infringing on the patent and went away happy because he had solved the problem, understood it better and understood how his solution worked.
if I had said here is the code I would have been in trouble, he probably wouldn't have understood it and if it had been used in a comercial product I could have lost my job.