Any art on the internet without a copyright is the internets.
That's why I build everything I make on a foundation that has my name built into it.I also repackaged all my bricks so if anyone trys to load a build I don't want to be public, the files wont match resulting in no brick loading..
If Klutz or I, or anyone else in Blockland were to put their name in their build somewhere, the build stealer would eventually find it and delete it.