The Aberdeen Effect is so named after a story of one person in a group suggesting a trip to Aberdeen and everybody saying yes. They arrived 8 hours later and nobody knew why they had bothered.
This is an example of pluralistic ignorance - when one person assumes that others in a group must have knowledge and conforms to their behaviour despite thinking it incorrect or pointless. An obvious everyday example is attending a meeting. Another is that embarrassing scenario in which a group of people may be queuing outside of a closed door when a single distracted person just opens it and walks through; everybody had simply assumed that the others had information about the state of the door that they didn’t.