Thanks to Richard Brett, Ocal now has the ability to detect when there is a potential copyright violation, and display a warning message.
It will activate on the tags pd_issue and potential copyright violation only so far. I'm attempting to hack it a little bit to allow a few other tags such as copyright violation - without interfering with the code in a loopback situation.
Clipart that definitly breaks copyright is hidden by librarians. These will be tagged as copyright violation. This doesn't get the message but will proably be hidden. So only librarians will be able to see these clipart anyway.
All of the below will now get the violation message, overlaid on top of the clipart preview.
Clipart that maybe breaks copyright and needs more attention will be tagged as potential copyright violation.
Clipart that has some issue about whether it is in the public domain or eligible for CC0 will be tagged as pd_issue
I have yet to figure out how to not annoy the librarians with this toy, but maybe it will be ok. We'll see.
Edit: Strange. Librarians can't see the violation message, yet admins, regular users and anonymous browsers can. This is a good thing but it confuses me as to how I managed that. Must be something in the user settings.
Edit2: Also Strange. Some cliparts are not displaying the message even though they are tagged.
Edit3: Sigh. When styling is turned off in browser, the violation message appears at the top of EVERY clipart. All I can say to that at this stage is, don't turn your styling off. :-)