Regarding the difficulties with knowing when to message and when not to:
I would think it would be a different thing if the fake/forgery was sold as such. But I believe (I think)
ebay has a Policy against selling forgeries.
You could check the policy ruling and then politely warn the seller about it, quoting it or linking to it. Or you could out and out report it.
ebay (I have read elsewhere) will respond (sometimes with unneeded vigour) and remove the listing or warn the seller themselves.
Sometimes sellers do not know all the policies of such a huge site like
ebay. Also, I think
ebay's policies seem hidden away and hard to find at times. You need to use the correct wording that they use to find them while searching. They do not link other similar words to it sometimes. So you could miss something. Unintentionally.
Highly unlikely, but possible. Thus the polite heads up.
Do not feel too bad. There are always people not knowing enough about some things (like stamps) so they will buy anything. I was once there. I bought garbage. I learned after a while. Then I bought better stuff. Sometimes garbage also but better darn it.
There seems to come a time when you have learned enough to 'get a feeling' about something. But, still, you could ignore your feelings and buy that good looking stamp. Unfortunately some sellers seem to make selling to unknowledgeable and/or inattentive buyers a full or part time job.
I have had cancellations on stamps that I questioned because they were too good to be true (centered, legible, etc, etc). One has to make a study of these things it seems in order to learn and recognize what is what. What is an original, what is a fake, what is a really good fake that you're not really sure about. Thus, for those able and willing to pay, the expertizing services.
Some forgers are considered so good as to be artists themselves. And people collect their work.
I do not think there is an easy answer for every situation except to say that if you feel it's wrong, then listen to your feelings, and hope to learn, and act so that you are doing the right thing, not to be right.
Why are people throwing rotten tomatoes at me?



I philosophize too deeply at times.
I yield the soapbox to another . . .