useability issue with iproute2 -- unexpected behaviour

I tried running the command "ip ro del default table 100" on a system that did 
not have advanced routing support compiled in.

Let's just say I was kind of surprised when it took down the default route on 
the *main* routing table.

Is this expected behaviour?  I would expect some sort of error saying that 
routing table 100 was not accessable, or something similar.

Thanks,

Chris