I agree that the final decision on how to respond should be in the hands of the host. But I think the host needs of few options to help. A few options could be added to the control panel. You cant' control the postal service delivery.Earlier this year I sent some seeds that the member said had not arrive after a couple of weeks so I resent the seeds but added tracking. They received the second package in a few days and then received the first one about a week after the second. So a mail by date rather than a receive by date would be better. Also some drop down options to the control panel could be used. Tracking required/Not required, Must be sent to host by Priority Mail required/Not required. After these features are in place the host would need to state in the Swap description, what their response would be for failure to comply with the rules.