When public good provision entails site placement decisions, public goods can become a private bad. In these cases, public goods have locally concentrated (subjective) costs caused by geographic proximity to sites. Prominent examples include the locations of wind turbines or hazardous waste disposals. We study whether this challenge extends to 5G mobile network expansion, a hotly contested issue in many Western democracies. Is opposition to 5G network expansion driven by “not in my backyard” (NIMBY)-effects? Can the widespread exposure to such local bads affect aggregate public policy preferences? We study these questions based on original public opinion data for Switzerland, a global frontrunner in 5G network expansion. Notably, public opposition to this expansion has picked up recently, both nationally (initiatives calling for a moratorium on new antennas) and locally (contestation of existing projects by residents). Combining conjoint and vignette survey experiments, we seek to understand public preferences on the 5G-rollout, and the extent to which it depends on geographic proximity to antennas. Drawing on a survey with geo-coded respondent locations, we randomly reveal actual 5G antenna placement to survey respondents and assess policy preferences when the “veil of ignorance” on the geographic distribution of antennas is lifted. We find that respondents are sceptical overall, and prefer a cautious rollout. Geographic proximity increases opposition to a 5G rollout ex ante, but decreases opposition once an antenna has already been placed close to respondents. Our research has implications for how the distribution of costs and benefits affects public good provision in democracies.