Originally Posted by
Sober Lark
Aer Lingus seem to be the only airline at DUB that double check your boarding pass when you board at DUB.
Suppose this person wasn’t spotted? If his only intention was to travel to Birmingham and nothing more sinister would he have been caught by security/passport control in UK?
As flights between the Ireland and the UK are classed as within the CTA - Common Travel Area, then he may have been met by UK Police / Special Branch checking IDs on arrival. However, this is not mandatory and usually only takes place randomly or when a name is flagged up in their systems. It is just left to the airlines check-in / boarding agents to check valid ID against the boarding passes on these routes.
Generally though, when arriving into Ireland from the UK, a Border agent has always checked a document. Note, legally this does not have to be a passport on these routes, just a valid I.D.