Hmmm..... I am wondering if experience SA can't really tel the bag is real or fake then how the forum can authenticate base on pictures??
Fair question. I will just give you some "unofficial" thoughts.
First, every sales associate has a different level of experience. Some probably could make accurate assessments. Some, no. The important point is that Hermes would rather not be in the business of authentication.
Next point--all opinions given by the authenticators here are just that--opinions. If you read the first post in the authentication threads, it emphasizes the point that we are a community offering opinions. An important distinction.
When clear and adequate images are provided along with the full and pertinent history of the seller, it is possible to make well formed opinions. The members here often have decades of collecting experience and are able to know fairly quickly if something is wrong. Perhaps it is as simple as an example of wretched leather, incorrect color or details, or something else. But it is possible for members here to see details that raise red flags.
When making decisions about authenticity, one important point to remember is that we are a community of collectors. Can one authenticator make a mistake when offering an opinion? It is possible--but in that case there are many good sets of eyes and opinions can be changed as debate and discussion and further examination of an object take place. Part of the opinion-building process can involve discussion and self-correction, all in the public eye of the forum.
There are three possible answers to authentication questions here--fake, good, or "cannot say based on the information provided." When the authenticators are unable to make a pronouncement or uncomfortable with an ambiguous listing, they simply say that they do not know with certainty.
No matter the answer, though, everything in the AT should be considered opinion.