I'm also not familiar with this legalese stuff, however in the case of Bluetooth, it has been "illegally" implemented in many (mostly imported from far east) devices that use it but don't show its complete name. If you encounter a Bluetooth device that claims "BT version x" compatibility and not Bluetooth version X, then it might be one of them.

This makes me think that should Thread gain some traction among users, cheap clones implementing it under a similar name, yet without any licensing, would appear shortly on sale at the usual vendors.