With the acquisition of UMTS licenses Mobile Operators (MOs), have often been obliged to deploy 3G network infrastructures covering at least a given percentage of users by a given date. This paper discusses the rationale for imposing these minimum coverage requirements by regulatory bodies. To that end, a model is built, which studies the incentives for MOs to compete for market share and over coverage within an unregulated environment where MOs are assumed to be free to enter sharing agreements and to negotiate a reciprocal roaming charge. Within this framework, it is first shown that MOs would deploy their infrastructure to guarantee the coverage of the entire territory (population), but they would avoid any network duplication in order to maximize rents from roaming revenues. It is then discussed whether a minimum coverage requirement is the best policy to reduce these excess rents, or whether alternative measures could be adopted which could serve other goals as well, such as the avoidance of network duplication.