This paper describes the results of a Wizard of Oz study of people's search behavior using BuddySystem, a proximitysensing system designed to help end-users locate people, places, and things. BuddySystem uses distance estimation based on signal strength alone, since direction is difficult to obtain in ad-hoc radio-based systems. Overall findings indicate that the BuddySystem changed people's search behavior to reduce walking area, but may increase search times if the system demands too much of the user's attention, suggesting that reducing distractions and adjusting search strategies could improve search effectiveness of proximity-based tracking systems in physical spaces. Keywords Proximity sensing, Wizard of Oz, BuddySystem