Thanks for the comments, but that still doesn't answer my question, and ultimately got nowhere, however, that's the general trend of this board, so okay, lets roll with it. To make things clear -
1. We had four people in on EA from various places, and we "grabbed" land by erecting a large shade structure and parking our cars/tents around it. We were actively using it from the moment we dropped in, and we filled it in with all of our campers. As I understand it (as told to me by the placer of my theme camp last year), there are no official rules regarding land grabs pre-entry above G street in unplaced camping, just courtesies. We did not flag off a massive chunk of empty land, but rather immediately built infrastructure and filled it in with our own camp. For the record, "unplaced theme camp" was our own unofficial designation, and not given to us by anyone. For the record, if you've ever been in early, you'd very quickly observe that land-grabbing with caution tape/rope/cones/cars is incredibly common. We decided to try to construct and use our space as quickly as possible. Our shade structure is 30x30.
2. We had planned our arrival prior to the gates opening, because we aren't stupid and we've done this rodeo before in different ways. We had pre-selected a few blocks to locate ourselves on, and those of us with EA were to build the basic infrastructure, post up a sign at a pre-destined sign-post, and everyone would meet us in camp. The plan broke down in that our sign was taken from the sign-post that we had posted on, so rather than sending our campmates on a couple-o-block long scavenger hunt, we texted folks. We were inspired to use a technology-free solution at the behest of this thread.
3. To make things abundantly clear, it was not one of the white posts used by ESD/Medical/Rangers/Other official capacities, but one of the tall T-posts with street signs on top. It was not on the edge of the city, but rather, a few blocks in. There were no other signs on it other than the official street signs on top, eight or nine feet up. We posted our sign at Eye-level, it was made of good quality wood that was not flaking/chipping, probably about 1.5'x1.5', and secured with zip-ties through a couple of attachment points. We tested it by hitting it. It didn't move. There was no way it was going to go anywhere, unless someone snipped it. Which brings me back to my original question:
Are we not allowed to post signs/notices/minutia/whatever on the sign posts prior to gates opening?