When trying to log in, I frequently get the following error:

Warning! The following errors must be corrected before you can login:

    Your request could not be completed because we have detected that you are connecting through a proxy server, or your IP address has been used for spam. Please connect from your real IP address.

I think the problem is that all major German ISPs have run out of clean IPv4 address space months ago, and just keep delisting their burnt IPs at Spamhouse&Co. Would it be possible (and safe enough) to change login behavior so that it only performs a spam check when new users try to register?