I would think with the millions of songs and registrations coming in all the time, the feelings of ASCAP, BMI, SOCAN,etc would be that if you don't care enough to list all the nessasary information as far as publishers, etc. why should they be interested? It is your song.

One thing everybody should probably do is to form their own publishing company. it might end up being just a "holding tank" for information, but would list your song in case something happens. In my experience, publishing is going to someone else until you are establishing yourself.
But it beats leaving the space blank.

In this day and age, we are all our own publishers, pluggers, artists, producers, management firms, etc. until someone else finds enough potential in it to take it off your hands.

MAB