Most of the larger manufacturers will require you to sign their submission documents before they will look at your information. These documents are designed to protect the manufacturer against an individual’s claiming that the company took his idea. The submission documents usually state that by signing them you are aware that they may have already seen, been working on or previously rejected the same or a similar idea. If you want to move forward with them you must sign these forms.
Submission forms that you send to manufacturers can also be considered part of your “paper trail” of proof that you disclosed your invention to them should you ever need it. Be sure to keep copies of everything in your files.
If the company is not ethical and you show your unprotected invention or idea to them, they can simply take it. Therefore, the thing to remember is to make sure that you have carefully followed your early protective procedures before approaching anyone regarding licensing. They protect themselves and you should do likewise.