As a flat battery or lost connection is a highly likely reason for a missed check-in, a low battery will trigger a reminder to charge the device and log a low battery message. Contacts may check their VIP's last known status, location and battery level. They may also check-in for a VIP if satisfied the VIP is OK.
In case of missed VIP check-ins or contact responses, a backup phone service can ring with voice prompts and keyed or voice responses.