Of course it is an honor system, it wouldn't work any other way. Youtube is an honor system (sort of, it has a bit of technological micromanaging police force built in), they can't have a staff member check every single video that gets uploaded for copyright validity. Of course people should be honest. That's all fine and dandy to preach philosophy about how everyone should be honest (and they should!), but in a practical world you have to admit that everyone is not always honest. There are dishonest people. And as such the need for copyright laws. The problem with copyright laws? They're out of date, they take too long to adapt and change to new emerging technology and ideas. They're too complicated. They don't cover what's right or wrong and are often written at the diction of large powerful media corporations who care more about making money then appropriating credit to original artists/credits. From a practicality point of view no one cares if you port models, sounds, maps, etc.. for your own personal use. If no one else see's it, no one knows it happens and no one makes a fuss. If you start publishing it though and trying to distribute it to others you'll find yourself in the realm of the criminal. People will put up entire movies on youtube and then put up a brief description that says something like, "THIS IS NOT MINE. NO COPYRIGHT INFRINGEMENT INTENDED. SUPPORT THE ORIGINAL CREATORS." And then cite the fair use clause or something like that as if that were sufficient to excuse themselves from breaking copyright laws/stealing ad revenue off of someone else's work. Additionally look at it from the perspective of the creator in varying situations: 1) They see that you made some fan art of your book, they are happy. 2) They see that you copied your book and are selling pdf's for $5 on the web. They are sad and are losing money from lost potential revenue. 3) They see that you are claiming they painted your oil artwork and pretending they are the originator. They are furious. 4) They claim to be associated with your company and are pretending to be an official retailer/representative of your company and are selling cheap knock off productss that make your entire company look bad and tarnish your good name. As far as I'm concerned, if you are doing anything other then some variation of 1, you are doing it wrong and should feel sorry. Anyway there's my opinion on it.