Anyone with a keyless entry on their vehicles use a Faraday bag to prevent thieves from doing what is called a "relay entry?"
Is this only for those who are paranoid or in high car theft areas?
For an explanation, a Faraday bag blocks radio signals from electronic devices.
"Relay entry" is usually done by two people. One picks up a signal from an electronic key fob or keyless entry unit and transmits it to another person near the vehicle being stolen. My knowledge on this is from reading an older article and there may now be ways for someone to copy a key by being close and stealing the car without an accomplice.
jtk