I applaude you for being one of the biggest and one of the first to permanetly publish quad A's. Really. Very gutsy.
But since I setup my proxy [squid3] on my server [Tilaa VPS 3.2.0-30-virtual #48-Ubuntu SMP] with the latest and greatest Ubuntu 12.04, all my drones are being forced to out themselfs as human by your [admitedly, friendly and well readable!] captcha.
Multiple times a day.
Ubuntu has by default enabled the IPv6 Privacy Extensions [RFC 4941]. This is nice, and in my book something that is desireable, but with the captcha's poping up all day long it gets old very fast.
Google, would it be feasable for your guys to tweak the 'monitoring for robot access' script a little and check for robot access not on a per IP[v6] address but on IPv6/64's?
128 bits of thanks!