This is of no danger to anyone, but a friend of mine has a 2 year old Caddy. When she parks her car on the North side of the local JCPenney store her remote door locks will not work. If she parks on the east side they work fine. The problem only happens there and can be duplicated each and every time. The service dept can duplicate the problem at that location but no where else. The only thing they have come up with as a possibility is the RFID transceiver at JCPenney. Her answer is “just park on the east”.
Could be a reflection off the building from a high powered FM or TV transmitter nearby, or a harmonic from a combination of sources like that. Anything powerful enough to cause a problem like that should be fairly easy to identify if you have the right test gear and knowledge of how to use it. The RFID transceivers have very low effective radiated power. I doubt that is the source. There might be a cell site on the roof of the JC Penny's that could be interacting with a high power RF source, causing a harmonic that the door locks don't like, too. That would be the first place I'd look.