Question about the draft

In sections: B.1 Simple Examples

Please explain why this is true:
        -- sending host 10.0.0.4 fails (reverse IP is not valid)

Is it because the IP address is an RFC-1918 address?

If yes, then what would have happened if:
$ORIGIN 0.0.11.in-addr.arpa.
   4           PTR bob.example.com.

And the sending host was 11.0.0.4?

Thanks,
Guy