Why are subnet routes lost when IP is flushed?

I am setting up a routing table associated with a network device.  Several
subnet routes are added to this table.

I notice that when I do 'ip addr flush dev [dev-name]' all of the subnet 
routes
destined out of 'dev-name' are purged!

Is this a bug, or is it supposed to work like this?

Thanks,
Ben

-- 
Ben Greear [off-list ref] 
Candela Technologies Inc  http://www.candelatech.com