"It's a bad winter and there's a sickness going around Leaf."
Haha, hello, biologic warfare, good to see you are still around.
Seeing the gokucoinTM mining process, it seems plausible to catch counterfeiters now that it all is being put together in a single place. All pieces match each other by the wood grain, making up a series of reconstructed tree trunks, which can then be assigned to their extraction sites by size and grain matching to the stumps.
If there are more trunks than stumps, it is proof of counterfeiting and the counterfeiters sourced from a different site, and we can search for it, again, by matching the grain. If there are less trunks than stumps, we wasted a lot of time and effort in a gruelling jigsaw (force wall?) puzzle and have nothing to show for it, because duh of course this section of forest is being cut for reconstruction or whatever, also some of the pieces were burnt down remember?
Also maybe check wood types before all this effort, it could be as simple as that.
Even if we do not have the means to actually detect counterfeits, seals are bullshit. We can pretend to develop a seal to aid in the detection of counterfeits, then set up a slow-going screening of the recollected scripts, and see who shows up to try and burn them.
I personally suspect the hokage of orchestrating this. A way to bind the goketsu and cripple their ability to try stupid shit, and all without bloodshed? Yes please.
So maybe we do not want to really know the culprit. Which was actually us, by the way, by deciding to pay actual money for pieces of lacquered wood.