Bonhams Boat-Lamp: "Collection History"? You've Got to be Kidding.

Bonhams have just sold an ancient Sardinian bronze object for £ 2,422 to a collector as Lot 83 in their "Antiquities 7 Dec 2021", sale in New Bond Street, London.

A Sardinian bronze boat-shaped lamp Nuragic Period, circa 8th Century B.C.

[...]
Footnotes
Provenance:
Private collection, Austria, acquired in the 1960s in Vienna.
For a similar lamp [...] see Kunst Sardiniens....[...].

I'm not kidding, the all-important collection history really is relegated to a footnote and really does say refer to an old Austrian collector who allegedly bought it "in Vienna" sixty years ago. Hmm. The all-important question is where was it before "Mr Anonymous-Austrian-(presumably-now-dead)-collector" got it, reportedly by 1970? How did it leave the soil and territory of the source country? Without the answers to those questions, this is only a "they can't touch you for it" provenance. It in no way establishes licit excavation and export before it "surfaces" in these records.

    Photo dated 1993 in Becchina archive showing what
seems to be the same object (photo C. Tsirogiannis)  

Prof Christos Tsirogiannis suggests there is part of the collection history missing precisely here (Dalya Alberge, 'Antiquities for auction could be illicitly sourced, archaeologist claims' Guardian 7 Dec 2021). It turns out that while Bonhams swallowed the (verbal?) assurance that the object was "in our collection before 1970" and seem not to have taken the steps needed to verify or falsify that, there actually is evidence suggesting that what seems to be the same artefact was in the possession of Gianfranco Becchina. How can this be?

On what basis do auction houses base the statements of the collection history of the  objects they agree to sell? It seems not enough questions were asked by the auction house when they agreed to host this sale to avoid the suspicions that they were duped with a false declaration. So why is that not reflected in the phrasing of collection histories? Perhaps one day we will see an honest dealer that is more careful about nuancing the degree of knowledge and verification "Said to have been...", "reported to have been...", "hearsay suggests that...", "the consigner asserts/ guesses/ insists/ suspects...", "we don't actually know, but this might have been...who knows?", (and of course in the case of some dealers, of course not Bonhams, "we don't actually know, but if anyone asks, you could say that..."). Of course the other honesty is an upfront: "Object excavated at ... in 1979, lot accompanied by excavation permit and official protocol transferring title, a verified export permit issued by ... on.... and full documentation of transfer of ownership, certified copies of which will accompany the object to the buyer in accordance with company policy".