Abstract: This case study describes an Android-based feedback mechanism, created to gain structured input on prototypes of Google Maps Navigation, a mobile GPS navigation system, during real-world usage. We note the challenges faced, common to many mobile projects, and how we addressed them. We describe the user flow for submitting feedback; the resulting feedback report from the team's perspective; our triaging process for the high volume of incoming data; and the results & benefits gleaned from using this system. Learnings and recommendations are provided, to aid mobile teams who may be interested in developing a similar system for their working prototype, particularly if real-world testing is required.