[wp-hackers] Write Post form validation before submit

[Jeremy Clarke]

There may be a more automated way to do it, but if you're going to
actually write your own plugin code then you should look into the
filters called by wp_transition_post_status(), you could check for the
value there and set the post back to draft if its missing (and figure
out the error display to the user seperately).

-- 
Jeremy Clarke | http://simianuprising.com
Code and Design | http://globalvoicesonline.org