I'm sure that many are aware of the big names like QxR, UTR, etc. They always add their names to the filenames so that people know that its their torrent; however, this isn't exactly a secure method for people to know that it is indeed their torrent, as anyone can easily impersonate one of those big names by renaming their file. Why don't people just add a signature to the torrents that they release? That way you can verify if the file really does belong to who it says it belongs to. Of course, this would also necessitate some means of distributing a public key.

I guess signing them would change the hash of the file, if you include it. this means ... its harder to share the same file if multiple people sign theirs and upload as individual torrents