Picked this up on another site... http://zernerlaw.wordpress.com/2014/02/25/open-letter-to-the-wga-board-members/

I actually read it all and it's not as bad as it may first appear. In a test case used as an example in the article the plagiarised writer would not be able to claim for damages if the stolen story crashes at the box office. However, if one also has copyright (as opposed to just registration) then one can sue for damages even if it fails at the box office... potentially putting the prod co. out of business.

I used to be lazy and only registered some of my work then as I got better, I started doing all of them. Then I started writing almost exclusively features and I switched to Copyrighting with the Library of Congress. I no longer register anything with the WGA.

I've said it elsewhere, and will say it again.  LOC copyright costs almost no extra than WGA, and offers huge advantages in terms of length of protection, forms of protection, etc.  And, given that shorts can be submitted as a compilation - why would anyone choose WGA instead?  (Sorry, WGA.  Love you guys otherwise!)