This has been mentioned in threads on Jaxels utilities - the stock XF does not seem to keep track of why new registrants are rejected. I have received a few emails like this: "I would like to use your site but your not taking new accounts. Why is that. Thanks, Gavin" ...and have no idea what to loosen up so these valid members can participate. I also cannot report to them why they were rejected. Hopefully this is in the feature list. I'd call it "registration intelligence"....we admins like to know all.