To make the problem a bit more visible, an example: We all learned at least one language at school (our native one), so we are not allowed to use the knowledge to use this language comercially (i.e. writing a book), right? Wrong, I say! Tutorials are for learning, and we should aprcieate those who write the tutorials. But if we say we couldn't use that what we learned from them, we can never use anything we have learned. The only thing we can say ist that it might be a bad move to use an object created 100% with the help of a tutorial for comercial purposes, but there is nothing illegal by it, or that schould be viewed as illegal, since this would be the fact with everything someone has learned. And that would be the end of society as we know it...