IANAL but my understanding is that giving someone something is not the same as giving someone a license to use it. If you have your neighbor permission to use t

IANAL but my understanding is that giving someone something is not the same as giving someone a license to use it. If you have your neighbor permission to use that five feet then yes you can revoke it. But if you instead gave your neighbor that 5 feet then you would not be able to revoke it. A key part of most open source licenses is that the author is not giving up ownership of the code. This is why many projects require a copyright reassignments for contributions to avoid being hamstrung by an author revoking their right to use that contribution sometime in the future.