GymHenson: Would a scum!Joe have risked saying he used his power and maybe being proven wrong by a town with a PR that could disprove such a claim?
dedoporno: There is a also a scenario where scum!Joe was afraid of a Tracker or another similar role if he did something else other than nothing.
Also true. In fact fact it doesn't have to be a Tracker or similar role. Practically any role. Even the lowly fruit vendor can disprove a commuter shot if he visisted Joe and wasn't blocked.
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PS, addition to my hypothesis:
Joe is Town OR Commuter is a safe-claim given by Pooka OR Joe is a Mafia Commuter
Really being a Commuter could also explain the claim. Is Mafia Commuter even a thing? I always though of them as Town, but I guess you never know.
Corrorolaororoalarrry of the above hypothesis:
Joe is Commuter OR Commuter is a safe-claim given by Pooka
(since Town shouldn't lie)