I have a similar application for RFIDs at the hospital, you can imagine the problems we have with keeping track of surgical instruments in a large operating floor. There has never been a accurate count of the number of instruments we have but I have conservatively estimated it at over 50 000 individual instruments. Throw in the fact that once a pan has been wrapped and sterilized you can't see inside the package to ensure all the pieces are accounted for and in the pan, imagine how a doctor feels when he opens up a patient to do surgery and all his instruments are either not all there or a small piece critical to an instruments operation was lost.
I proposed an RFID identification program about 3 years ago with each instrument receiving a unique identifier implanted in each instrument, it's actually quite easy to do since a grain of rice sized RFID can be placed with a simple hole drilled in each instrument and then sealed with epoxy. At the time the supplier I talked with quoted me a cost of $1 for each RFID, add the cost of a scanner in the wrap rooms and other key areas and the costs were estimated at $250 000 plus the labor for implementation.
Of course I was met with blank stares from those in charge and because the technology was not well known at the time there was zero support for such a project. Unless there was a standard set for the industry to follow with harmonic frequencies set aside for each type of instrument and without instruments being manufactured with imbedded RFIDs I'm afraid the idea is dead in the water.
I believe the bible predicts we will all be identified by our left hands from birth and when that happens it is a sign of the coming apocalypse, at any rate I will continue to wear my tinfoil hat for protection and keep my left hand in my pocket.
Its the devils work I tells ya!