Development of Creative Commons licenses

["Dr. Augustine Fou" <acfou AT PictureSandbox.com>]

Hi Rob

First off, THANK YOU for taking the time to give comment... understood it is not legal or official, but for discussion. 

referring specifically to

"What you could do is to use or set up a service that grabs the image
metadata at a particular time to confirm that the image was available
under that license when you or your customer used it."

here is a sample license 
http://picturesandbox.com/license/27i8d5sf

at the current time we get whatever information is publicly available on Flickr, where the image owner released the photo under CC. The license itself is simply a "screen shot" of the CC 
3.0.  But this screenshot goes into the calculation of the "fingerprint" which is an SHA512 hash of all the info on the page, including a date/time stamp from the NIST Atomic Clock which we ping at the moment of consummation of the license between the image owner and the end-user/licensee. 

The purpose of this was to protect the licensee (in case the image owner changes their mind later) by providing an auditable document which not only includes the terms of use (CC v3.0) but also the date/time, the details of the photo, and details of the two parties. 

The more difficult "what if" is the case where a "bad actor" steals a photo, uploads it to Flickr, and sets a CC license to it. But clearly it is their wrongdoing that could result in a CC photo being improperly licensed by an end user -- and hence this begs the question whether 
PictureSandbox.com is required to "look" at each such photo to verify copyright. 

- Augustine