Those who are most invested in the event make the call. They have put months of sweat equity into planning the event, they stand the most to lose financially if it is cancelled and they clearly will be the most disappointed if it is called off.
Those who are least invested in the event are the ones who are deciding whether to attend or not. They look up at the sky or at the Weather Channel app on their phone, see that it is raining or sure looks like it could, and decide to make other plans. If they were in charge, they would pull the plug early and move on. Many probably suspect that the event isn't even being held.
More often than not, if the event is held, it hosts a fraction of the attendance that would make it spectacular. A few die hard fans watch from their cars or brave through the mud with umbrellas, but it isn't really the fun festival that the organizers envisioned.
Similar things happen all the time where the most invested are making decisions that are different than the least invested would prefer. The IT department buys a sophisticated software system that the end users hate. They don't buy a simple program that the end users would really use and could benefit from. Companies invest in expensive professional development for staff, but don't provide them with basic supplies to do their job.
If you are a decision maker, think of what those impacted would want you to do. You may move heaven and earth to make the concert happen, but the audience would rather be home and dry instead.
-- beth triplett