It's similar to the type of games people play with their 4x4's and GPS systems in outdoor adventure in the wild.
We have done something similar for a team building event, but we had to look for clues to a treasure hunt. The clues were scattered all over the city and we were driving like crazy to find the treasure.
This concept could open up a new influx of Bitcoin adopters in the outdoor & entertainment business AND people organizing team building events.
The thing I like most, is the outdoor aspect of this. People are motivated to excercise and go outdoor to find these coins. They could also include this in the dating scene.. where people could take part in activities like this, and then be rewarded, with a lunch paid in Bitcoin, if they complete the tasks and find each other.