There is a difference between being NOT AIRWORTHY because it actually is unsafe and being labeled NOT AIRWORTHY because the right paperwork wasn't done - but the MOD and many posters here believe the two are one and the same.
And many posters here ascribe themselves the powers of the Almighty. How on earth do you know if something is safe when you instal it, when you service it, when it gets older and older if you don't keep a fully audited paperwork trail of its history?
All the bits that were installed on the Nimrod MR2 to provide it with AAR capability were presumably considered safe but the installation did not conform to the Airworthiness Regulations. As is the way with airworthiness shortcomings fate took its time to strike, but strike it did.
All the bits that comprised the MB Mk10 ejection seat were considered safe, so safe indeed that a Safety Case did not even exist, lots of paperwork saved there! As is the way with airworthiness shortcomings fate took its time to strike, but strike it did.
Would you buy a used car purely on the verbal assurances of a glib salesman, or would you insist on seeing written evidence of a full service history? After all, it's just so much bloody paperwork...