Protection Stones and Grief Traps have no correlation. They are built by players (primarily staff members) and the Admins set them out in various locations across the map. They may appear as an ordinary house or they may appear as a simple construct or monolith. It's hard to tell, since they are cleverly placed in locations of particularly high traffic. Not even the admins know where all of the grieftraps are (which adds to the un-disclosure of their approximate locations).
We currently have enough grieftraps set up in the world as of right now, but feel free to make one if you have the resources and send a Private Message to an admin of the building's coordinates.
Also, if you haven't put up a Protection Stone yet, your build may be susceptible to some form of grief if you're in a particularly high-traffic area. If you have your chests and doors locked, you should be safe from theft in that regard but not from grief entirely.
That said, the griefer can still be caught if it is brought to the attention of the mods early on.
