The multi-messenger era is now well-underway, with high-energy neutrinos providing a unique opportunity to study particle acceleration. Recent reports describe possible coincident detections of a single IceCube neutrino with a flaring blazar. While compelling, these sources cannot be considered in isolation. I will present various strategies to put these associations into the context of the relevant astrophysical source populations. Firstly, we can use the non-observation of point sources in IceCube searches to place constraints on the high-level properties of the unknown source population. In particular, current measurements disfavour populations of rare and bright sources. Secondly, simulations of proposed populations and their transient behaviour can be used to evaluate the probability of chance coincident detections in a principled manner. Finally, these simulations can also be harnessed to predict the contribution to the overall neutrino flux that is consistent with the proposed source-neutrino association. I will demonstrate the application of these methods, using the proposed detection as a case study. The results raise further questions for the bigger picture of neutrino astrophysics.