In most cases the fraud takes place when the counting is done.
I remember reading about the way it was done in Detroit in 04. When republican observers complained about blatant fraud they were removed by police. A quick injunction ordered them back in but they were locked out anyway.
The observers said they were openly throwing votes for Bush in the trash and filling in empty democrat slots on ballots.
Yes. One typical pattern is to ask for more ballots because of the “crowd”, then ask for a time extension, then get certain observers out, then start filling in names and casting ballots for them, but not all of them until you hear how many are needed.
In some areas they go for broke and just make the turnout be 100%.
You’d think, though that since so many know how it’s done that there would be ONE bust of such a factory. That’s a major problem with the concept.
One problem is that this happens in places where you can’t legally run a video camera on the door and count.