Illegal voting is already illegal, and states can already in theory do shady things in their elections (and some probably already do). The courts should absolutely go after this, and I don't see NPV really changing this.
> The NPV system focus the most energy on states with a high population in this condition.
Perhaps so, but the one of the main points of NPV is for state boundaries to be meaningless for campaigning. Maybe politicians should spend more time in densely populated areas because, well, there are more people there.
> What would happen when there are charges of skullduggery? Would states really trust, with no power to verify, other state’s returns?
Do states currently trust that other states hold fair elections to determine how their electors vote? I don't see any change here.