Have you ever done that trick with a car key where you can remote open the car from a really long distance?
Most remote keys work from about 10-15 metres (30-50 feet). However, you can double or treble this distance if you hold the key to your head when you plip it.
I don't know how it works, although I have some theories, but it would be good if someone knows the real answer. And its a great party trick when the car is right at the end of a long car park after a tiring day.