Gonzales, Fiesler, and Bruckman  had studied the choice of technology with communities engaging in a scavenger hunt. Spreadsheets and Word documents were favoured over specialized applications. Simple low-cost solutions are easier to replicate.
Gordon and I had discussed this concept a while back - leveraging scavenger hunts as means for Technology Stewards to train with the community. The FrontlineSMS, Freedom Fone, and Ushahidi tools can be combined to exchange clues and information.
 Joseph A. Gonzales, Casey Fiesler, Amy S. Bruckman (2015). Towards an Appropriate CSCW Tool Ecology: Lessons from the Greatest International Scavenger Hunt the World Has Ever Seen, Computer Supported Collaborative Work (#cscw205), Vancouver, Canada.