An RFID system and method utilizes an RFID device, wherein the RFID device senses a thing or condition interior to a closable container at or proximate the RFID device and transmits messages. The messages include information uniquely identifying the RFID device and information relating to the thing or condition sensed at or proximate the RFID device. Information in the received messages relating to the thing or condition sensed at or proximate the RFID device of messages are employed for determining whether the container is closed, is not closed, has been closed, or has been not closed, or any combination thereof, whereby an opening of and/or tampering with the container may be detected. Messages received from the RFID device, as well as an indication of a condition, may be relayed to a remote location.