@Gary825 If the guest wants or needs to cancel, it is up to the guest to cancel. If the host wants to cancel, it is up to the host to cancel from their end. Courtesy has nothing to do with it, unless it was the host who wanted to cancel and asked you to cancel from your end.
You don't just automatically get a refund because you cancel- it depends on the cancellation policy in place for the listing, which you agreed to abide by when you booked and the reason for the cancellation.