I couldn't have put it better myself. I don't think the person who wants convenience has enable on any ASes routers, or at least I hope not. One thing I find interesting is that they're using 169.254/16. Doubtful Google uses DHCP for anything, their automated provisioning tools are probably quite unique. My best guess is that their stuff in that particular part of app engine is using the space because they've actually near exhausted the rest of rfc1918, which is pretty impressive.

The only other organization I know of that has done that is Comcast, which has been a leader in forcing vendor ipv6 support because they literally exhausted 10/8 for their management networks.