Well. Of course you're right, but...uploading parts while the file has not completely been downloaded has always been one of the best features in ed2k protocol. It assures that files are spread MUCH faster because you don't have to wait for the whole file to finish before you can upload.
If you have problems with fake files, there are some projects out there which could help you, for example the ed2k-search-engine jigle.com...there r also some programs for fake checks, but for windows X(
hth,
Citroklar