Bri you presumably mean Bristol (BRS) ?
Whatever decision the airline made at the time was up to them, no solution is going to be ideal and a number of passengers will be inconvenienced. The options are to cancel, wait for passengers to be bussed from ORK to SNN or go empty and hope to get into ORK with the return load. Previously EIR kept people waiting round for ours only to cancel flights at the last minute (typically around midnight, agter 3-4 hours of delays) when crew were put of hours and there were no options for reaccomodation. At least by cancelling early the team on the ground can get working on reaccomodating passengers as soon as possible and minimising disruption/discomfort.