'They Can't Touch you for it Legit'

ARCA blog: October 1, 2015  'Christie's Withdraws Suspect Antiquities from Auction'.

Christie's has withdrawn the suspect antiquities identified by Greek forensic archaeologist Christos Tsirogiannis, on September 29, 2015 that had previously been set for auction today at Christie’s in London.  

This is a recurring pattern isn't it? A load of antiquities are posted up for sale with collection histories of varying completeness. Some of them are identified as potentially dodgy by outsiders, those are taken down. the ones that had not bee identified before the sale are auctioned. In what way was the due diligence done by the seller before the auction different for those groups of objects (Christie's)? Or can we just say that the ones that make it to the auction block are just 'they can't touch you for it ligit'?

UPDATE
Anyone reading this now, go and see the live auction, the auctioneer is a scream.  Brilliant. Who is he? Unlike certain of their competitors, I think most of the objects sold by Christie's are what they say they are. One or two items today looked to me (in my personal opinion) a little of dubious authenticity and it was noticeable that bidding on them was either slow or failed to reach the reserve (with one exception which had 'cuteness value').  Those rich people are not stupid, and those industrialists either have a good and informed eye, or advisors who see things the same way as I do Unlike last year, the bidding of the Roman glass was disappointingly sluggish.