Isn’t it a security feature linked to a max load or a category of cargo? It could be a good reason: “Mixing cargo and luggage is only allowed on planes with a s

Isn’t it a security feature linked to a max load or a category of cargo? It could be a good reason: “Mixing cargo and luggage is only allowed on planes with a secondary extinguisher” => We sell the secondary, not because security is optional, but because we sell the ability to do something more with the plane.