Everything with Blackmailer stays the same except BMed characters voting notifications in chat are invisible, both voting for trial and voting inno/guilt. results of vote from that character would still show, making it harder to detect bm but still possible. obviously being able to say blackmailed when on trial would remain.
A key part of meta and major weakness with BM is spamming votes to communicate BM, its objective is to silence a player but this only works before voting for the most part. not sure if this would be too powerful, but it def gives it a boost. may be too OP for early game in this format tho.