Atom Editor - can't disable spell checking (as default) while simultaneously allowing spell check toggle

I want to disable Atom spell checking as a default. At the same time I want to be able to toggle spell checking on and off.

To disable Atom spell checking by default you disable the core package spell-check. To allow spell check toggling you can edit your Atom keymap.cson file as such:

'atom-text-editor':
  'your-custom-key-combo': 'spell-check:toggle'

It's required you enable spell checking to use the custom toggle shown above. I want spell checking disabled by default, and I still want to be able to toggle when necessary. How do I do this?