FWIW, I've checked the "Ignore automatically obtained routes" checkbox in the "Routes..." dialogue. I'm going to see how it goes. So far I've reconnected to Freenode, Facebook and G+ after unplugging my network cable to clear the route list, and so far the route list hasn't grown from the default routes set up when I reconnected the cable.
FWIW, I've checked the "Ignore automatically obtained routes" checkbox in the "Routes..." dialogue. I'm going to see how it goes. So far I've reconnected to Freenode, Facebook and G+ after unplugging my network cable to clear the route list, and so far the route list hasn't grown from the default routes set up when I reconnected the cable.