Rat, You are most likely correct in following the tech log philosophy... once the capatin accepts the aircraft warts and all etc...
In reality, even the acceptance staff can only check the outer containers, hazard labels, handling labels, specification markings (if applicable)and so but cannot open the package to check the inner packagings, materials, etc. The Shipper's Declaration for DG (the DGD) is the legal document which clearly puts the responsibility for for declaring, packing, etc... squarely on the shoulders of the shipper... not the agent not the acceptance staff, not the airline, not the captain... the shipper. Nobody but nobody can alter teh content of the DGD. As I understand it, the Captain is the end of the chain of people who deal with the DG. By signing, he is simply acknowledging that he has been told about it.
He is not responsible for the correct packaging, labelling or documentation. Arguably perhaps he is responsible for its security and safety on board his aircraft but only if it was suitable for transport by air in the first instance. If it is not suitable and something happens, then he is really a victim of somebody else's perfidy and/or carelessness. I rest my case.
DC8rider.