This is an issue that can get some members very angry.
I also agree, for the most part, with Dave that if you release something on the Internet, via the DLS or a third party site, there is a good chance it will get copied with or without your permission. Some of that "pirating" will be through ignorance - such as a recent example here where a young kid did not realise that what he was doing was wrong. Others will be with the full knowledge of what they are doing but with an "I don't care" attitude, ego, an over inflated opinion of their "rights", a false belief that "freeware" really means "free" - the list of reasons or excuses is long.
Those creators that put conditions on the release of their work (e.g. not to be posted anywhere else or altered without permission, no modifications allowed whatsoever, not to be used as a part of any payware, etc), while they are totally within their rights to do so, are really attempting the impossible. Once something is posted on the internet, it is out of your control. If you don't want your work to be modified or copied, then don't post it.
There have been many threads and arguments in these forums over the issue of copyright, and no doubt these will continue. N3V have a very clear, and I think very reasonable, policy. If an asset is posted on the DLS by another user that the original creator can show is theirs, then it will be removed but the complaint has to come from the original creator and not from another user who believes (no matter how strongly) that the work has been pirated.
Yes, it would be nice if, at the very least, a "thank you to ..." or "modified with permission from ..." was included in the description field of a copied assets config.txt file, but this is unfortunately the real world.
As to what can be done? The discussions here have been long, often full of justified anger and frustration, but with no real solutions. Vigilance by the community of what is posted on the DLS is often the only way as N3V do not have the staff to examine the microscopic detail of every .jpg, .tga, .im, etc file in every posted asset and automated software has far too many flaws to do the job. How can a software algorithm judge if one file is a "substantial copy" of another file if human juries cannot decide if one piece of music is a copy of another?
Then what about assets posted on third party sites?
HiBaller's solution is one possibility but then only the original creator will know what to look for.
The discussions will be endless.
A member of the "Party Machine". Now if only I could remember where they are holding the party!