It looks like you never approached the fine art market, it is worst there believe me !!
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This said, from my short experience in movie posters and here, I can say there are indeed some secrecy... I guess the fact we are an inner circle of people with specific interest makes things difficult when it is about speaking publicly or semi-privately about bad apples. If you ask advice on forum, precautious reply is all what you get :p
as shysters go, the movie poster hobby has the least of them. Comic books and baseball cards, probably have the most. But that doesn't discount the coins hobby, the sports hobby (with massive frauds that have been perpetrated by some big players, like Mastro Auctions which resulted in jail terms) or a number of other hobbies like Coca Cola collectibles, automotive collectibles (plates and the like, not talking about the cars) or another hobby - Modern Art, which could possibly be the cheatingest, if you count by dollars spent.
but you have to ask what a shyster is. Is a shyster a person who just asks big prices, or people who are always trying to stab others with false narratives so they can claim a high ground over others, but are no better when you really discover who they are. [for the sake of this debate, we leave the complete thieves out of the picture, the forgers and the like. A crook, meaning a person who robs you by intentional misdescription, printing bootlegs, or forges Universal horror posters is clearly a top level shyster.]
shysters take many forms. They aren't all about stealing
back to the subject at hand.
James, it is important for people, especially dealers, to have the correct data when they sell. This is generally accomplished by having a philosophy that you don't want offer a piece that is of some questionable information. One reason is that - most especially in the internet era - any mistake you make gets propagated throughout the system. If you call a poster an original release when it is a reissue, that information gets assimilated and creates confusion, for years to come.
but that is a mild issue that is more easily corrected than others.
let's take the Vacation 'teaser' one sheet that we discussed recently. Only one place I know has sold & described the poster in this way. When it was asked how that determination was made, the one place pretty much refused to answer, no matter how many times they were asked in that thread. Completely non-helpful. People are asking because they want to know. If you know, post the information. If on the other hand, the whole definition of this poster is based on nothing more than "we THINK it is".. that's a mistake, and it's a willful mistake. (does that make the people who refuse to answer such questions a 'shyster'?)
so yes, it is important to get the right information
don't get me wrong, I totally understand that people make mistakes, but you don't compound it by making more mistakes.
I also can understand how a big business, staffed mostly by non-poster collectors, non-poster dealers and short-term experienced people can make mistakes.
For instance, in my world, one of the identification methods may not actually come from a visual inspection - it may come from a handling inspection. My fingers touching the poster in question and feeling the surface of the paper might make me suspicious, or the thickness of the paper. This can't be taught so easily, it has to be learned over many years with the help of other people who know more than you do. So if the person(s) who 'know' haven't handled the poster and a neophyte is writing the description, you are more likely to result in mistakes somewhere along the line.
One of the great things about movie poster people is that they will share information, even if as BigBoss mentions, sometimes the information isn't easily forthcoming because as collectors, sometimes you want to wait until you have your copy, or as a dealer maybe you want to be able to score some profits by being able to buy an item without competition, but overall, we are happy to share. This is how lots of bootleg posters are discovered.
But another part is your biz philosophy. I refuse to sell material that I can't properly identify or which has some known issue. Sometimes I have a poster and I say to myself "what exactly is this?" and I have 50 years experience (I started selling comics in 1966! and I have posters I got in 1967). Not everyone has that ideal. Some people just have a need to pump it out like Wal Mart pumps out $5 shoes and so posters that I would not offer until I can make a definitive determination, others will create an identification and sell it. Then later when the real determination has been made, go back and change the data - creating a different history than what really happened. This is not my method. Correcting my own mistakes is not an ego-building moment.
this is why it is important to listen to other experts and actually absorb the information, whether you want to or not.
