We dont know if yellow rags are guessing based on what Geoff says or does Geoff have a friend working at one of those rags, hears about what is gonna be published the next day and gives an 'educated hint' based on this info. But as soon as he says anything it spreads like wildfire.
There is definately a pattern of Geoff posting a vague hint about something happening and then the next day Daily Mail, Mirror etc. have a very similar story published.