I use a similar approach. My community is exclusive, and my policy for years has been that you have to ask to join. I kept registration deactivated and had an announcement visible to guests telling hopefuls to use the Contact Us link to write to me. I would then temporarily re-activate registration so the prospective member could register. Lots of users joined that way, and I knew that spammers weren't going to write to me. Since activating PBR, I've been able to re-activate registration, and almost no spammers even try to register, because they're too busy "posting" ... or at least they think they are! 😉 With this feature and the spam control rating option, it leaves very few IP addresses, user names, and email addresses for me to Google and run through WhoIs, Project Honeypot, etc. It's working out great for me.