ksvalidator - can't detect errors?

Sometimes ksvalidator will complain but not return an error, for
instance:

   # ksvalidator -v RHEL5 /tmp/tmp.57yMAuel5v
   The following problem occurred on line 2 of the kickstart file:
   Unknown command: somesetting1
   # echo $?
   0

I want to be able to detect such problems.  But when I try to
redirect or pipe the output of ksvalidator, it produces no
output.

How can I detect such problems within a shell script?

Fedora 14, pykickstart-1.77-2.