Boarding card
As Ryanair no longer seem to print things like the passport number on a boarding card, what's the real purpose of asking for it at all ? Does FR run a check against an immigration database to confirm validity of details before issuing the boarding card ?
As long as the name and the nationality on the boarding card match the passport and the photo in the passport resembles the passenger, gate staff will let the person presenting the boarding card onto the plane.
Apart from traffic between the UK and Ireland, I've never seen immigration staff in the EU ask for the boarding card of an arriving passenger when the passenger holds an EU passport. Further, if a passenger wanted to 'lose' their boarding card in the hours between boarding a plane and arriving at immigration, it would not be hard to do so.
I'm just struggling to see the point of the insistence that passengers must supply their passport number to Ryanair...