What I don't understand is, how come you're not allowed to for example, get someone's song lyrics into your own song for free, yet it's OK to get someone's gameplay idea/concept into your game for free. For lyrics you have to pay the license to the original author, for the other it's free for all. It's the same creative thought process that brings both kind of things into existence, yet one is treated differently. Sure, it's about the execution, but shouldn't the author of the original idea get some kind of royalty fee off of it, even if it's just a small cut?