When bringing up an interface specified as nogateway in /etc/conf.d/net with udhcpc, a default route is still set. baselayout passes this option to udhcpc via a PEER_ROUTERS environment variable, but udhcpc doesn't do anything with it.
Created attachment 99602 [details, diff] udhcp_nogateway.diff
Fixed in cvs. Thanks for the patch :)