On this one mate I always sign the DGNs as when you go to the docks / railhead with a container (as I am on containers as well) I have been turned away at the booking in desk cos the DGNs haven,t been signed by either me or the driver who collected the load.
Also once at Felixstowe I was turned away because the “loader / responsible person” hadn,t signed the DGN`s either on behalf of the manufacturer / warehouse!
You as the driver are as far as I am aware (but I stand to be corrected on this one by Dave) are not responsible for the actual load in the container such as it being segregated correctly if it is a mixed load.