Originality?

There has been some discussion, (primarily on Scoundrel and NSU's Card Talk) about 'copies' of sketch art - the most recent example being that of a Brian Kong sketch of Albert Pujols (made for a Topps sports set) that has, to be scrupulously generous, been 'emulated' more-or-less line for line by another 'artist' in a card listed on eBay. I will not name names as far as the seller is concerned, nor will I post a link (if you want the details, visit either of the aforementioned forums!)
The topic also came up during a recorded concersation I had with an artist for the next episode of UK CardCast, and it got me thinking.

Art has, throughout the ages, been inspired and influenced by earlier work. It has evolved and expanded and explored new types of medium, new styles and new subjects. At the very heart of it, however, is the sense of new artists learning from the old, new styles being developed by those given experience of the old styles. As part of the education (whether formal or informal) artists learn from their mistakes, learn from the limitations of their chosen medium and, above all, learn from their predecessors - and in that respect, there is a certain amount of copying that goes on, if only for the exploration of technique, or the desire to explore the boundaries of variation.
Artists have taken subject matter that interests them and have adapted it to their own style, usually adding their own touch of originality to the original and so making it different and unique. Roy Lichenstein used the imagery of the comic strip to produce his legendary 'pop' art; Andy Warhol used pre-existing imagery (grocery labels, iconic photographs) to produce some of the most well known 'modern' art of recent time. Those artists, and many more, both before and since, have added to the originals and created a whole new piece of art.
However, with the use of such methodology comes great responsibility, and in recent years some 'adaptations' have cause controversy. Damien Hurst was criticised for one of his pieces (entitled 'Hymn') which appeared to have been based on an educational anatomy model (Wiki here); Shepard Fairey used a photograph by Mannie Garcia as reference material to create the iconic image of Barack Obama used to great effect in the 2008 US Presidential Race. (BoingBoing article here)
It is the latter example that is most relevant to the current issue over the alleged reuse of a Brian Kong sketch by another artist. In the Brian Kong case, a card he did for a Topps set, which was authorised by Topps and the relevant image rights holder, was 'copied' by another artist who, presumably, does NOT have the authorisation of Topps, or the subject of the sketch, Albert Pujols (or his personal or team management nor that of the relevant sport governing body), the copy being made not for the enhancement of drawing skills, or for the personal study of sketching technique but for profit - the card is, as I type, on eBay (having been sold and relisted).
How different does a piece of art have to be to be unique? Can an artist take a copy of an existing image, add a little crosshatching, or tweak the colouring, and thus claim to have produced a '1 of 1' unique image? Should said artist reveal that he/she has used a pre-existing image as the basis of their own work? Should they seek permission from the originator of the existing image? Should they credit the originating entity? What happens if the original image is officially licenced to someone else?

"So What?" you might say, "How does this affect me, the Non-Sports card collector? The Brian Kong card is for a sports set!" Well, yes, it is, but artists who have worked on non-sports sets have already reported copies of their work being offered for sale, usually as '1 of 1' cards and with no indication that they are not original pieces but copies; in one or two cases, the cards have been offered under the name of the original artist and so can be considered fakes or forgeries. This sort of thing does not reflect well on the hobby, and exposes the collector to potentially expensive risks.
I'm not criticising those who use other images as reference material; most who do add their own individuality and their own original touches and enough of both to make the end result an entirely unique item, and usually do it within the generally accepted 'code' of behaviour!

What am I trying to say? Well, "Buyer Beware" probably, but it's a shame that people who (possibly) have a talent and who could be capable of great things if they used their own imagination rather than indulging in a line for line appropriation of someone elses feel the need for greed seem able to not only get away with it but who also manage to turn the collector into a more cynical person. We need less cynicsm in the hobby and more creativity.