Lol, you are joking, right? You actually believe that you need documentation to copy something and sell a similar product? C'mon, ever here of Transformers? How about Go-Bots? How about LEGOS and Kiddicraft Blocks? How about Hydrox cookies and Oreos? What about all the products Samsung makes that blatantly copy Apple, like their Tablet, phone, appstore, home designs, etc... Where is the paperwork for those stolen ideas?
Ever walk into an ALDI grocery store? You think all those knock-off brands have contracts with the name brand companies they are ripping off? No. They just make cereal that looks exactly like cocoa puffs and tastes ALMOST like cocoa puffs, but they call 'em choco-balls.
How about Walmart? You think they need written documentation from Dixie to make their own brand of paper plates, or just about anything Walmart makes their own brand for? No.
If you believe game companies can't skirt around copyright laws the same way every other corporation that copies it's competitor, than you (not you, just anyone who follows this train of thought) are just naive.