When I was trying to test how the router running IOS release 12.4(15)T5 classifies inbound IP packets into various CPPr subinterfaces, I wanted to use the log action in the MQC classes I've defined. This approach worked perfectly for the host and cef-exception interface (I've even seen ARP packets logged), but the packets classified as transit generated no log messages. While this makes perfect sense (after all, all punted packets are processed by the transit service-policy), the IOS should generate a warning when you apply a policy-map with the log option as service-policy on the control-plane transit interface.