My theory of S&R is that day hikers - and spur of the moment hikers-- are in a more serious situation than when a backpacker gets lost...

Also:

- leave your itinerary with a trusted source
- carry extra water, compass, jackets, etc. ( google " the ten essentials" for a variety of lists of gear.)
- most smart phones have some sort of gps function. All GPS have this function
- A 'signal mirror' is cheap; I pay between $2.50 and $10 per unit. And you can learn to use one in 5 minutes.