Some background information is relevant to many of the ETI contact scenarios discussed in the rest of the paper and is thus worth considering separately and in advance of the scenarios. This background concerns why we have not yet detected ETI (i.e. the Fermi paradox), the challenge of interstellar communication, why ETI are likely to be more technologically advanced than humanity, what we can learn about the ethics held by ETI from the study of ethics held by humans, and the possibility of heterogeneity within an ETI population.