This is the first time I've seriously investigated the issue, though. Another example: the two Stolen Data tunes are also known as "d-funked memory" and "sky drift". (Also, "stolen data6 tune" and "stolen data tune" are exactly the same as each other, so I have no idea how that ever got uploaded.)
You see, this is the problem. I rename all my files "author_mod name", always have done, because cryptic filenames back in the days were a pain in the arse to organise and keep track of.
I then send 5 or 6 CDs/DVDs to AMP or Modland. I think the 1st lot I sent to here was 18,000+ modules. Of course they get added I presume, but I doubt every last one was checked thoroughly. Although I tried to send everything that I considered not on AMP, I know doubt that some were bad rips, different filenames/filesizes or whatever... But that was like 3, 4 or 5 years ago, not sure, maybe longer....
I still find modules today beacuse of the different filesizes or I identified wrongly the author/filename, even Modland contains dupes still. As a basis, I still use AMP as the main place to check for Protracker modules, I just wish the search had better facilities.
I don't use AMP or Modland to check for PC formats, ie. s3m/xm/it. I sent Coma 4 or 5 rar compressed DVDs a number of years ago, so effectively those are on Modland. I again think that even those aren't 100% accurate.
As the tracker module scene has dwindled, I find less and less time to track down and download files or just not bother at all. I doubt there are many people who want to be involved in it, even though a lot of people still find mod music relevant and want to listen to it, for whatever reasons. Apart from AMP/Modland allowing some admin rights to the database, it is down to just 1 or 2 people to maintain the sites. I noticed that Modland hasn't been updated in awhile either.