The ultimate Carryon I guess.
Tis a few years ago but friend was among crew on Aer Lingus Transatlantic flight when a baby born. Question asked by media about Nationality brought a very quick response from an senior Irish Civil servant. Friend kept news story in a scrap book.
Civil servant just said as baby has Irish Grandparents then it is entitled to Irish citizenship and then added even if it didn't I doubt it would be an issue for anybody and congratulations to the parents and welcome to Ireland.