Well, in my opinion a ban list based on file ID could be useful, even with the limitations posted above, when:
- A file is presented with a different name than the one you remember and you can't check the alternative filenames (because there is not a copy with the other filename actually online or you are using a remote client aMuleGUI or aMuleweb)
- You can't easily look at the file comments (again, mostly when you are working remotely)
And, of course, with the high amount of fakes on the network, is unlikely that someones remember exactly any fake encountered. Often, doing searches in aMuleweb, I ask myself : Have I already downloaded that? Was it a fake? Or the fake was that one with a similar-but-not-exactly-the-same name? (this is worsened by the fact that in aMuleweb you don't have, at the moment, color-coded names for the files you already downloaded)