Adding a notification to the change column window is good but it won't resovle the use case where a new user logs in and has no columns selected, never clicks change columns, and tries to export without ever opening the change columns window. 

The note and code I put above is actually something I don't _think_ will work. That was why I mentioned views at the end but I haven't actually looked at how marionette does the event bindings yet so I can't confirm either way.