If you are auto-voting that way, then no human being makes a decision about whether the new content created by these authors are any good at the time. The idea of shadow voting I can decide to subscribe not to vote on the content you create but to vote on the content you vote for. That way there is still a "brain"in the process of deciding what to vote for. Should anyone post badly they wont be voted by a good curator.
This is a way of farming out voting decisions to more people. So not only can use up all of our voting power to the max but you also reward a wider set of authors.
The only way to keep complete control is not to use any auto-voting at all. That's what I am doing.