How can I change the "Ask to join new networks" option using a terminal command?

We are currently switching to a new wireless network throughout our school district and I have pushed commands to connect to the new and remove the old. However, any Macs that have "Ask to join new networks" enabled are jumping over to our unsecure guest network, even if that network has been removed from the list of Preferred Networks. So far the fix has been to remove the guest network from the list of Preferred Networks and then disable Ask to join. The only issue I'm running into now is I have been unable to find a terminal command to change this setting. Once I have the command I can write a script and send that out to all of the Macs.

So is there a way to disable "Ask to join new networks" using command line?