@BOOKHOUSE You could give out something actually physical. Like a set of coordinates that gives a location to pick something up.
@retech i am doing that for most other treasure hunts. Write book. Hide treasure hunt in book. Hide treasure in UK. First to solve and find it has it.
This one i want to be a little more automated. The prize will always be there and anybody who solves it has access to it. So i can create essentially the same treasure hunt in different ways and share that out in special made books.