It would be a shame to lose this. We were discussing the idea on OVDB. It was Enelysions idea. Interception detection chips. They consist of photovoltaic cells, volatile memory and battery powered extended range RFID chips. The volatile memory contains a secret 'not compromised' string and is attached to the RFID. It also contains some simple programs, primarily a program that broadcasts the secret string after some time delay (alternatively broadcasts the secret string in response to another secret string being broadcast to it, although this requires broadcast of the pick up agent and may deanonymize them if LE are waiting for them with radio frequency analysis equipment at the pick up location). The device is set wirelessly after being placed into a closed package. If the photovoltaic cell is triggered by light, for example when customs opens your package, the secret string is removed from volatile memory so customs agents can not reconstruct it. After some time delay, the extended range battery powered RFID begins to transmit the secret string, or perhaps begins to transmit a pseudo random pattern that uses the secret string as the seed (this will allow for verification of the secret string being present and make it so that law enforcement can not rebroadcast the secret string if they identify the chip and rebroadcast what it transmits after the time delay runs out). Now you can tell if your package was opened prior to picking it up from your fake ID box, merely by analyzing the radio frequency spectrum near your box location. Extended range RFID can broadcast signal significant distances, and as no broadcast is required to activate the interception detection chip it will be very difficult for law enforcement to identify anyone performing such radio frequency analysis near the box store. Additional detectors / triggering mechanisms can also potentially be integrated, such as oxygen sensors with the chip vacuum sealed with drugs, or x-ray sensors, etc. This sort of defense is strongly related to concepts from the field of measurement and signature intelligence, MASINT. Such chips would likely cost under $10 each to create, although some custom programming would be required to configure them. As far as size goes, they could be pretty small, probably about the same size as a quarter maybe a little thicker.