A quick and dirty solution would be to just add a script that runs every check in to remove that SSID from the preferred networks.

networksetup -removepreferredwirelessnetwork en1 SSIDHERE

The solution I found was to set up a configuration profile with a preset for the public SSID and garbage authentication method and credentials, thus preventing the computer from ever successfully joining. There isn't a way to blacklist SSIDs in OS X.

Joshua, I've tried this but the client just corrects the authentication method and then allows the user to re-enter the password. Am I missing something?

There are posts from last year sometime where someone wanted to blacklist certain things. Several of us contributed scripts of varying success and I even tried my hand at an awk only version that kinda sorta worked.

Search around a bit I forget who it was…

I looked through my post history:

https://jamfnation.jamfsoftware.com/discussion.html?id=5327

peineke - for those 'quick and dirty' solutions, where would one put that script to be run when a device checks in? (Newer Casper user here...)

Thanks.