The source isn't Twitter, it's the Sun, which is kinda the point.
What kind of access to db's will they have? What agreements are in place? And so on.
Neither side wished to have its citizens unduly inconvenienced if they were tourists or business visitors and existing arrangements for these categories of passengers were agreed to continue. If the EU has decided to renege on what has previously been agreed, then their citizens will have the delights of joining the queue at our arrivals controls.