I think Mr. Simpson was referring to the outbound traffic in this case, not FULL transit. Of course you have to manage a way for that traffic's return packets to find you. In a lot of ISPs cases, the outbound traffic is a 3:1 ratio. So if you can dump your outbound traffic onto an unknowing IXP member, your probably in luck. Then just simply order an SMDS connection to CIX for the return path at ever-so-fast lightspeed.
Presumably most people monitor for this though or they deserve all they get.... One simple way to check for people defaulting at you is to ping from an IP address which is not in the routing table one of their IP addresses, and apply a logging filter for dest addresses of the nonexistant IPaddr on the i/f over which the peering occurs. If you see ICMP Echos to the nonexistant IP address you know they are defaulting. (This isn't my original idea - apols to whoever thought of it originally if they are reading this). IP accounting / flow stats are more reliable though. Alex Bligh Xara Networks