Haven't followed this closely, but I look at hip hop (and, I suppose, electronic) producers in the following way regarding sampling:
If a producer "discovers" a sample in a pre-existing song -- meaning finds a bit of music, isolates it, and then loops it up over and over -- and compliments it with new drums and bass (and other sounds), and gives a rapper a new canvas to place lyrics over, said producer basically creates a new work of art (even if it based heavily on that existing music). I find that of value. I enjoy the art of sampling. They are basically re-purposing that initial pre-existing song and adding enough new elements that they (and the rapper) are then associated with the pre-existing song. They've introduced it to a whole new audience that may have never been exposed or appreciated the initial work. I would describe this as an nbd. Like taking an existing trick to a new spot.
What I find less impressive (though, on occasion, still of [albeit lesser] value) is when a subsequent producer utilizes the same music sample that has already been re-purposed, or even less impressive, samples the actual song that the first producer created with the sample already contained within it. Sure, a different rapper may be adding his lyrics now...but a producer (and rapper) has already planted their flag into that sample. It's inherently kind of an abd.
Now, the record industry has decided that, in all occasions, the original creator (or the otherwise owner of the work) has to be asked for his or her consent/approval, and be given credit and (at least the opportunity) to require financial participation. The risk the producers and their record labels run is that the original creator/owner can put an injuction on the re-purposed music, having it pulled from shelves, or even demand most of the money earned from it to be given to them retroactively.
I personally am not a stickler for giving credit or payments -- I think fair use should be pushed to the limits -- but it is essentially the law. And giving the original creator/owner a say has some value, at least, for instance in a case where, say, a neo-nazi band wants to sample an African-American or Jewish artist's music; said artist has the right to prevent that from happening to their material.
Others, however, see no value in sampling and frown upon anything that isn't an original creation.
I guess I look at re-purposing art for skateboard decks, or placing an existing-song on a skate vid soundtrack, as my stance on sampling: It's cool to bring a drawing or photo to a new audience, maybe change it up a bit (or a lot).
But it takes on a new life, at least in my mind, when it gets put on a board, with the name of a company (or a pro's name) on it. Or if you hear someone skating to [insert song here] for the first time. It's an nbd. I see the value. If another company then subsequently uses the same graphic or skates to the same song, it's an abd.
But, yeah, I think it's a moral (and legal) question of if the skate company has to negotiate with and/or credit the original artist.