Not hard to replicate, though. A good, long piece of rope, something to flatten the stalks, and four or five cooperative friends is all you'd need to do it in an hour or two. You could really do it all alone if you weren't in a hurry and you had some stakes, but having at least one other person help would let you avoid leaving evidence in the form of stake-marks...
You could really do it all alone if you weren't in a hurry and you had some stakes, but having at least one other person help would let you avoid leaving evidence in the form of stake-marks... Who said there were no stakemarks? If you saw the little holes, would you recognize them as stakemarks? And, finally, if they mattered, why wouldn't the makers take an extra 30 seconds and cover them up?
As for precision, a couple of $2 pen lasers (1000m range) will give you all the precision you need. Although I note that we never see pictures from close up (at ground level) to check the regularity of the edges, the probable spacing of the board, marks from ropes, undisguised footprints, or errors, etc.