I forgot that I did actually get a reply from the 'ebay watch expert ' 2 days after I'd asked the question. It's obviously an independent business contracted by ebay.
He didn't answer my question, as his reply is mostly generic, as I imagine all replies are. He says there's a 10 point check, but what are they checking for ? He doesn't mention authenticity of functionality, just that the 'check'.
"Thank you for contacting eBay Customer Service. My name is Brandon, your eBay Watch Specialist. While reviewing your message, I noticed that you've been with us for over 13 years! I'd like to take a moment to just thank you for the time and loyalty you've dedicated to eBay, it's greatly appreciated!
We see you are inquiring about the item: Rolex Submariner Men's Black Watch - 16610 (126864055856), and you would like to know how this item is listed on eBay, when you have cited that it is potentially counterfeit. I am so glad you have raised this to our attention.
Sellers assume all responsibility for the content of their listings. We do have people and systems looking for suspicious items, and we are appreciative when we get reports for us to look into. Based on the detail you have provided, I am reporting the listing for review as a suspected counterfeit item.
The buyer that has purchased this item is well-protected. Our Authenticity Guarantee program listings will undergo a multi-point inspection to ensure they are authentic and as described by the seller. If there is a discrepancy found during the inspection, we take quick steps to protect you with a refund and return the item to the seller.
During this inspection the authenticator will do the following:
Performs an external 10-point physical inspection of the item covering: crown, bezel, dial, case, clasp/buckle, bracelet/strap, hands, movement, crystal, and end links.
Opens the watch and inspects the internal parts and components.
Check the water resistance of a watch using a dry tester for watches that have a resistance rating using a pressure test.
Performs light cleaning and battery replacement, as needed.
It has been my pleasure resolving and answering your inquiry today. Thank you for taking the time to contact eBay’s Customer Service. Stay safe and have a wonderful rest of the week.
Best Regards,
Brandon"