I similar encounter some time back as well. The organisers are a couple. So when it rain, they cancelled it and go pak tor. While I am left to find my own alternate plans.
While I agree that if it rains, we have to cancel the activity. But I disagree about cancelling the event totally. We can always find alternate activities. When we organise something, the participants has committed their time to us. They may have pushed away some other appointments. We shouldn't just cancel it totally at the last minute. At least should have offered an alternate plan. It it break down then so be it.