"If you accidentally lock your key inside the car and you HAVE a spare key somewhere in the world, by phoning the second key holder on your mobile and getting them to press the open button on their fob close to their mobile - you can open your door by holding your mobile close to the door lock. (No, I haven't tried it but plenty of folk have and have posted confirming that it does work and it's easy enough to test). Apparently it works from the other side of the globe too.
It at least saves you the problem of getting someone to drive out to you with the spare key, Not much help if you have only one key of course - but another reason for getting that second key cut.
(The same email gave this info too - but we can't really test it:
"If you should ever be forced by a robber to withdraw money from an ATM machine, you can notify the police by entering your PIN # in reverse. For example, if your pin number is 1234, then you would put in 4321. The ATM system recognizes that your PIN number is backwards from the ATM card you placed in the machine. The machine will still give you the money you requested, but unknown to the robber, the police will be immediately dispatched to the location").