If I just built a house, and if there were some definitive test to know the wood came from somewhere illegally, who would I sue?
In the US, you would sue the person you paid (who would then sue the middleman company who sold them the wood, and so on down the chain until the chain eventually ends).
It’s interesting to think what a market would look like if we removed indemnity and limitation of liability from contracts (which allows liability to easily be passed down to vendors) in certain cases. I think that’s how it works in certain other countries.
E.g. what if the liability was solely with the person who sold me the wood (even if they’re actually “innocent” and simply bought from a fraudulent distributor).
I can easily see how it would help to keep all liability at the closest link to the consumer in the chain, but then again how realistic is it that any home builder is going to (reasonably) be able to do enough vetting of distributors and suppliers to know exactly how and where everything was made.