NickB

uhh?? It is also a government safety rule that aircraft should be serviceable and comply with all safety requirements. Does that mean that the failure to fly an aircraft because it has not been properly maintained is not the carrier's fault because it is due to non compliance with a "government rule"?

It seems to me pretty clear that it is the airline's responsibility to have proper protocols to remove baggage from the aircraft without resulting in undue delay. As the Court of Justice of the EU would put it, this is "part of the normal exercise of the activity of the air carrier concerned" and cannot therefore be regarded as an extraordinary circumstance justifying exemption from the duty to pay compensation.

That, OTOH, I would agree with. There is really nothing that a carrier can do here other than divert and is sufficiently abnormal to warrant the label of "extraordinary circumstance".