Here is what I was taught with respect to CYA activity in the IP arena. Whether you are manufacturing or distributing a unique product or service yourself–this strategy may help.
I will try to make it simple.

Assess your market and the players maybe the top 20 percent–the ones with larger revenue (the reason for this is that they have means to tie you up in court–smaller companies will tend to stay away at all costs and will often abate the stolen idea when contacted-whether intentional or not) Send them a certified package or letter to the president offering them your IP–Then save all the return receipts from the post office–this is proof that those companies are aware of your IP. If they do come to the table the better for you and your position if you ever have to take them on –this stops the defenses argument of “innocent infringer.”

Here’s why:
If in the future you discover that one of these companies has infringed on your IP–you send them the usual cease and decist letters etc. When they do not comply and if their argument is they did not know(not a very good one)–you can then bring out the fact that you pre-empted this very strategy and have in hand the certified return mail receipts signed. Further, if you have to go to court and file a petition against them it makes the process easier because the judge can see that you indeed went to them first and instead of the issue being a costly patent infringement case it may turn the tables in your favor quicker. I did this in a federal case with a furniture design infringement and without hesitation we won even before it went to trial. Hope this helps.

Example of big company(as you say and are correct they do not want your ideas they have enough of their own) next:
Another time that this strategy was useful was during a chance meeting with the president of major outdoor product line while attending a trade show in Salt Lake. I was pitching my pack line and was abruptly interrupted by him, he said something to the effect of, “I do not want to see anymore–how do you know that we may be working on that very same idea?” My reply, ” You shouldn’t be my patent portfolio is probably sitting on your desk as we speak. he said, “how do you know?” I said, I have your signature on my certified mail receipt to your office. (he probably never even saw it -usually their mail room or executive assistant signs for those)I knew that he wouldn’t be interested in my design anyway but I wanted to meet him and let him know who I was.