Evidence now supports lightning-fast searches using libdoodle -- which in turn uses libextractor to gather all kinds of meta-data from all kinds of file.
This means that you can't just search for file-names, but for metadata as well. For instance, you'll still find that misnamed MP3 if the data in the ID3 tag are correct.
Modern formats like Ogg Vorbis or MP3 do not only allow you to store you music in compressed form, they also facilitate "tagging" it, i.e., storing meta-data like the artist, the album the song is on and the year when it was released in a portion of the file called the "tag." The standard that describes tags for MP3 files is called ID3, and few people know that ID3 tags may contain images of the artist, the album's cover, or a variety of other things. (Of course, the evidence file-manager supports ID3 and will display an image from the tag instead of the generic "MP3-song" icon if one is found.)
The common response to this gem is people calling such tags bloat.
The common response to that is that 10 KB of JPG image in 6 MB of MP3 doesn't exactly constitute bloat.
Sometimes, this answer is spiced up with a little calculation illustrating how many image tags you'd have to create before stealing diskspace for even one soundfile.