OK , you guys obviously know a lot more about this than me. The only time I renamed a file was when I was a kazaa user (gag) ... I came across a game that took 3 days to download and it was a completely different game. I renamed it to "THIS IS NOT xxxxxx" and purposely kept it in the download folder so that other people would know. (On kazaa you can see all the sources and the individual file names) This led to a lot of messages from users asking me if the content was correct and I saved loads of people from downloading it.
The main problem was there was about 75 sources of this incorrectly named file.
Of course, I don't have the time to police the whole network!!!