of course...the entire circuit can be located in the house/garage with just the switch wires going to the mail box...
The rf solution is interesting also, but I'm guessing it's only sending a signal when the tilt switch swings down on the door, and there is no mention on the receiver latching the activation...
Yes, there are plenty of other ways to perform this task, a simple relay, an LED and a resistor, but the disadvantage is the power consumed, a pp3 battery will last diddly squat time...Simple CMOS could also be used with a push button reset for instance, with slightly better power requirements, but using any sort of small micro will minimise the current drawn and can be in direct control over how much current is stolen by the LED by means of a cyclic, duty factor based indication.