facebook spam getting USER_IN_DEF_DKIM_WL

I (and a few others) have seen a wave of people trying to sign up for facebook with random emails 
across several unrelated domains, resulting in emails containing signup verification codes (eg "Hi 
X, We got your request to create an account. Here's your confirmation code:") hoping straight to the 
inbox due to USER_IN_DEF_DKIM_WL (even though I hit a 1.0000 bayes score).

I'll obviously just disable that locally, but it seems worth tweaking the score for 
USER_IN_DEF_DKIM_WL and/or dropping [email protected] from it at least for now.

Matt