Several years ago a family member was on a flight from JFK-LHR, which was diverted to DUB due to an electrical fault onboard. His final destination was actually SNN and DUB would not have been a million miles away but the airline would not allow him to leave the airport and insisted he wait in the lounge along with the other pax for 4-5 hrs and then continue to LHR on the same aircraft. Would this still be the policy today and in general would there have been any repercussions if he had simply left?!