on-interface routes

[Eugene M. Zheganin]

Hi.

Why bird touches on-interface routes ? Right now I have to create import 
filters and prohibit importing of on-interface routes, because in case 
of losing a link bird thinks that this route was added by it and deletes 
it, making the network unuseable. Is there a way to tell it 'don't touch 
on-interface routes' ?

Thanks.
Eugene.