This paper proposes simple but potentially quite significant ways to encourage useful emergent communication in MARL. The paper is well written with a nice empirical analysis. The reviewers had some concerns about the coverage of related work and the empirical comparison to Jacques et al. but it seems easily feasible to address these in the final version. The authors are strongly encouraged to add to the final version a comparison to Jacques et al. in Treasure Hunt, regardless of whether the results favour the proposed method.