I consulted a DG specialist, who is in IATA DG board. He also thought the CAO rules was actually stupid and useless. The very strict CAO accessibility requirement was in place but how could operator to follow? i.e. some classes or divisions DGR goods are required to be accessible during flight, but even so what can flight crew do in emergency???
Can you image that to ask flight crew take the fire fighter to put off the fire? Or removing the heavy skid and deal with the leakage by hands? However, the gross weight limit of some UN DG packages are around 400L or 450Kg.
The IATA DGR only regulates the DGR goods quantity for each individual outer package, but no rules for each aircraft type. Believe it's aircraft manufacturer''s responsibility to develop such rules. I did see the cicular from Boeing regarding the Dry Ice limit on B744 aircraft.
Besides, Li-ion Batteries/Cells are flying over the world by aircraft. Some Li-ion Batteries/Cells are powerful enough as the explosives and may cause mass damage to aircraft/human being/property.
Believe that no carrier will stop this service even realizing the risk of DG or hidden DG transporting, otherwise they can't survive.