With some co-operation from bugmenot they could return it in a machine-readable manner with the names of the form widgets to populate. Of course, for that to work they'd have to be submitted with said form widget names which might be a pain for people to get without viewing the source or some submitting browser extension. I suppose it could just guess some names like “username”, “login” and “user”, but then you get “email” and “pass” and “id” and… sigh.
I'm sure, since LJ registration doesn't give access to any new content, that they'd be happy to add livejournal.com to the block list if Brad was to contact them. It's clearly outside the scope of what they're trying to do.