I don't know if the moderators can find out who did it; but I would guess it wasn't one of the frequent users
What would someone gain from wrecking one of these. They increase their chances of being perma-banned and all it does is destroy another person's hard work.
The suspected griefer (player seen placing the sign) has been banned from EMC, pending an explanation and investigation into their involvement.
It has appeared that the stone one has also been trashed. I would go into more detail but I'm on an iPhone.