Hi,
This is something I noticed while I was playing around with my Triband connection on USB. If I start (or reboot) my router after my computer has started, the network interface for the USB connection is detected but not enabled automatically. I have to manually up the interface.
I guess this behaviour is expected under debian since network configuration (upping of interfaces) takes place only at startup through /etc/init.d/networking. Any network devices detected after startup will be configured but not enabled.
Shouldn't default behaviour be to simply enable the interface if it is defined as auto in /etc/network/interfaces?