Hmm ...

    $ curl --dump-header - 'http://shop.nordstrom.com/robots.txt'
    HTTP/1.1 403 Forbidden
    Server: AkamaiGHost
    Mime-Version: 1.0
    Content-Type: text/html
    Content-Length: 281
    Expires: Fri, 27 Feb 2015 23:42:13 GMT
    Date: Fri, 27 Feb 2015 23:42:13 GMT
    Connection: close
    ...

Probably a bad idea to deny serving robots.txt to bots (even if they ought to interpret that as a total ban)