That's absolutely true and this has been going on for years. A number of years ago US customs seized shipments of counterfeit Cartier and VCA Alhambra that had come into Florida. The pieces were virtually indistinguishable from the authentic items. Suddenly there was an influx of rare items including on 1stDibs of 20-motif turquoise and coral Alhambra necklaces. I know firsthand, because I bought one--which was successfully returned.
As a result, many dealers I know will no longer sell VCA Alhambra or Cartier bracelets because even they can't tell.
Something else that occurs is that photos are posted of a genuine item for sale which reveal the serial number. Counterfeiters have been careful to apply the same serial number to the same item so it matches in VCA's system. In other words, the serial number for an authentic 20-motif turquoise will be used on a counterfeit 20-motif turquoise. If a SA runs it thorough the system it will come back as matching, but that doesn't mean it's authentic.
When VCA reviews a piece for authentication, their conclusion states the item does not bear the characteristics of an authentic item. This means it could be counterfeit or it has been altered such that the specifications are non-conforming. In other words, you could own something that's authentic, but has been altered, so it's no longer recognized as a VCA creation by VCA. That's why it's important to have all repairs done by VCA, which they won't do without first determining authenticity. Easy enough if you have the documents, unless the documents are fraudulent or if it's flagged by VCA, in which case you have to go the full authentication route before VCA will do the repair. That's important to have if you ever want to resell it. It's also important in terms of value.
I see things all the time on
Fashionphile or TRR sold at near retail but without documentation. From the boutique, for $50 or $250 more you get the box, pouches, the COA, the receipt and chocolates. To me, that documentation is paramount. In other words, the savings is inconsequential to what you're
not getting.
There are certain older pieces that you can buy preowned with confidence--in fact that's the only way to get them as they're out of production. But more popular items, such as the Love Bracelets and Alhambra necklaces unfortunately attract unscrupulous sellers that attempt to exploit customers that want to save some money. And how else are you going to get that turquoise alhambra, other than to buy it on the secondary market?
Accordingly I buy from the boutique but I also buy preowned. However, I have several rules of thumb: 1) if it's too good to be true, it probably is, so DON'T; 2) Buy from a "seemingly" reputable dealer; 3) make sure there's a return option; 4) do not buy from an overseas seller; 5) ONLY buy with a credit card--NEVER do a wire transfer or pay in cash for jewelry, even if it's at a discount; 6) run it by a jeweler when it arrives and if you feel queasy then return [e.g., the "go with your gut test,"]; 6) if two sellers have the same item and one comes with documents and the other not, buy it from the former even if it's more expensive; and finally, 7) if it's a piece you really want and the cost is more than you can comfortably lose, have it authenticated. It's well worth the peace of mind, it will enable you to resell with confidence, and if it comes back as counterfeit, it will provide the necessary substantiation to give you recourse.