Zathan - that would be a good assumption for the API settings, but it doesn't work (and is why I asked Austin how to disable it and why he told me there wasn't a way ). If you select disable clay login the popup login window then appears anyway when the game starts... There's also no way of controlling the plugin's attempts to log in by using the event system. Frustrating!
I also just discovered a bug testing this - I can't seem to get the plugin to work in IE11 - it gives me a javascript failure (about to post it on the clay thread).