We want everyone who receives the source to know what we have done vs. what changes have been done by others that we have not yet approved. This is primarily an issue of quality assurance. You can, provided that the person you give it to has agreed to the license. The person does not have to physically sign the license, but they must affirmatively agree to the same license agreement. We have enclosed this agreement with the package.
Patents are like booby traps.
To the best of our knowledge we have not stepped on anyone's patents, but if we did, and we are notified of that fact, we must terminate the our license to use the offending code. You may find it helpful to use an automated service such as MindIt to monitor the website. Since we don't have the names and addresses of everyone who has a copy of the source code, we have no way to notify everyone in case of an infringement claim. Therefore we will do this on the website. We do not specify any specific time but every few months seems appropriate.