In Los Angeles and elsewhere there has been a rash of burglaries from vehicles utilizing an RF amplifier that will boost your key fob signal, otherwise too weak to open your car, to open your doors and trunk. The little black box amplifies your own secure code so that your car thinks you are standing at the door.
The thief then enters the vehicle takes what he wants and leaves. Most often they are on bicycles to make quick getaways. Numerous instances have been captured on video.
The solution is simple, use a Faraday cage type pouch or container to prevent the signal from reaching the vehicle. The author of the article I will link you to below suggests using your freezer which I don't recommend as that will prematurely age your fob's battery. Aluminum foil does NOT work, some dumbass news reporter here in L.A. (John Gregory) suggested that without even testing it and I can assure you it does not work.
Amazon sells Faraday pouches which are ridiculously expensive but will work. My wife, genius that she is found the perfect solution for us in our kitchen, reasonably priced, incorporating a sort of Faraday technology (the mesh metal screen on top) and it works flawlessly blocking the signal right next to the vehicle. Our solution is a stainless steel sifter with stainless steel screen built into the lid.
The media also recommends a microwave oven as a storage device, I don't like that solution either for obvious reasons.
I found out by accident the other night that the Hellcat FOB has impressive range. From 40 feet way through 2 load bearing walls and one interior wall I unintentionally unlocked the doors. Apparently, these amplifiers the thieves are using are sensitive enough that they can work with signals too weak to open the car by fob alone. The amplifier can take the weak signal and boost it enough to access the car.
I am not taking any chances some of thefts occurred within 5 miles of my home. I strongly suggest that we take this seriously, secure your fob.
I searched the forum didn't find any info so I thought I would share my solution. I know many have heard the story but apparently not enough to prevent the thefts that occurred last week here in L.A. News story video, etc. below photo.
Article regarding thefts: http://www.nytimes.com/2015/04/16/style/keeping-your-car-safe-from-electronic-thieves.html?_r=0
Fob guard: Fob Guard: Ideal Faraday Cage for Car Keyless Entry Fobs