Hi Andrew, I know where you are coming from. It happens all the time. And I know we at least have the courtesy of sending a private message or posting a cancellation note on the event if we do have to cancel.
The big question is what is the solution? Require a 48 hour cancellation? What about last minute emergencies? And since most events are free, no money is lost. It will be interesting to see what ideas come out of this.
I think the big thing here is common courtesy. Don't cancel unless you really have to (not that I just don't feel like going now) and let your host know.

