Many beginner editors don't understand that they need to match track artists to an artist in the database (turning the artist field green), and their edit is not being entered with an error message something like "You need to put a title and artist on each line". From their perspective they have put an artist and title on each line.

Perhaps the error message could be changed to make it clear that they have to match the artist to an entry in the database (and how to do it), turning the artist box green.

See the discussion in IRC for reference.