The opposite situation can be puzzling. When I had a National Challenger one-way out of LGA last year, I noticed the keychain had a barcode and 2 key fobs. The ends were shaped like a blunt, thick key, to be "inserted," or rather held in place apparently magnetically, into the ignition. The doors had the usual silver slot for a "regular" key, but there wasn't one on the keychain. I later did a one-way National Grand Caravan out of NJ, and realized it had the same setup.