I know FR don't offer connections, but with 2.5 hours planned on the ground DUB I should have had plenty of time to make my onward flight. As for who pays for the Connections security search, surely that should be a service that any airport provides free of charge, especially one that has "DUBHUB" logos all over the place. It would have been interesting if the staff at Connections had refused me entry with a valid Boarding Pass,but I'll never know because I'll never be repeating the transit experiment again.
Rules are you cannot but it's probally down to staff discretion. In T2 if you have separate EI to EI tickets and baggage checked through they would let you through.
The airport is focused on long haul connections not short haul ones. The T1 transfer facility closed at 13.00 is because British Airways, Flybe, Lufthansa, Finnair, Air France/KLM, Air Canada, WestJet, Swiss and SAS will all have completed any transfers to respective long haul carriers.
Why keep it open when there is no passenger data of traffic expected after 13.00 and no airline willing to pay for extra staff when they could be put to better use elsewhere.