Range Rovers are the most sought after for these electronic trickery thefts. They go into containers and moved abroad.. Average ordinary cars are fairly safe though. Most thefts are the higher priced and sports cars. You can put the key fob out of range or into a Faraday cage type pouch.
Never had a car stolen but when the cars were simple, if i parked in areas where theft might happen, i used to remove the rotor arm and take it with me.