Originally Posted by chubbs

These things sometimes disappear from dealerships before they get fitted to the car at PDI - and subsequently re-appear on Ebay. Sometimes the buyer (like you) knows they're supposed to have one, sometimes the buyer has no idea that part of their car has been stolen before it's delivered. Of course, there's probably a totally innocent explanation for yours not being in the trunk

It also happened to some of the bluetooth units on 350z's when they first got equipped with them.