We track campaigns through campaign-parameters but apps are a blind spot of course, that's nothing new. Relying on the referrer is stupid, most apps don't provide a referrer because they are Apps and not websites! Browsers provide a referrer if you are coming from another site. An App isn't a website, so there's no referrer.
Of course there's no referrer, it's a new browser window! Campaign-Parameters here would also not be very helpful. If the Visitor copies the link not from a guardian.com visit, but after coming to the story through a campaign-URL, he would copy the URL with the campaign parameters and paste it into the app. This would be even more wrong, but happens daily!
We Web Analysts should get used to it: People are becoming aware of privacy more than in the past and we can't always measure everything and everyone. Get over it!