The number of connected devices is quickly approaching 20 Billion thanks to the increasing availability of connectivity technologies and decreasing hardware costs and driven by a growing ability to mine the generated data. This market is expected to grow even larger if access to devices and their data were open, with a flourishing ecosystem of applications and services being created around them.Web of Things APIs are paving the way to standardize this process; however, with more access and more revenue come more responsibilities for device manufacturers and providers of add-on services alike: misuse of data and devices needs to be prevented and trust systems need to be in place to reinforce customer confidence in the resulting service systems. In this paper we discuss the opportunities and risks associated with opening up connected devices and propose a technical framework for regulating the resulting service ecosystems.