Further to the discussion on accessibility in flight, generally speaking the IATA DGR requires that, with some exceptions, CAO shipments must be accessible in flight.
Common sense says that I really do not want to be too close to Classes 6 or 7 (infectious, poisonous, and radioactive to the uninformed bean counters). With those exceptions, it is good and safe policy to have access to Dangerous Goods in flight. A 5 foot lance is all very well when the problem is just behind the barrier net but when it's "further afield" then you are in fertiliser country without a paddle!
Arrange a fam trip for the bean counter on your aircraft and, during flight (preferably at least 2 hours into an oceanic sector), express "grave" concern about some inaccessible "OK Pax aircraft" DG shipments.
Fear brings about a whole new set of opinions! He/she will have a more enlightened regard for safety and while you
have his/her undivided attention, explain the slogan "Safety is no accident".
Works every time! Oh, and by the way, suggest that the bean counter brings along a change of underwear. Could be useful!