scp_if_ssh not working as intended

[Marc Petrivelli]

I am trying to run the following playbook to deploy a key to a number of servers

deploy_key.yml:

- hosts: servers
  gather_facts: no
  user: root
  vars:
  - key_file: /root/.ssh/id_rsa.pub
  tasks:
  - name: add authorized keys
    authorized_key: user=root
                    key="{{ item }}"
    with_file:
      - "{{ key_file }}"

in ansible.cfg i added the following line:

scp_if_ssh = True

from the command line I am executing the following command:

ansible-playbook -k deploy_key.yml

 As expected I am prompted for my password and it seems to authenticate but when the play is run I get the following error:

fatal: [m-vc] => failed to open a SFTP connection (Administratively prohibited)

My understanding was that setting scp_if_ssh=True in the ansible.cfg file would force ansible to transfer files using scp instead of sftp.  I tried manually transferring a file on the command line using scp and it works fine.  Am I missing something here?