I have had some close calls with Ryaniar to make a flight when I have been there at check-in with plenty of time. I would suggest that any passenger in the terminal obtains some kind of time and date proof that they were there at the required time. A mobile phone photo of the terminal clock will be ok. If Ryanair cant process the passengers in time then its a simple breach of contract. I wouldnt hesitate to start a small claims if the airline couldnt fulfil thir obligations.