The pioneers were the Sanchez Sisters in Orange county, CA. Loretta's team just plain invented about 7500 voters. They also worked hard to illegally register aliens, legal and illegal, felons. The tech has matured to the point where CA is reputed to have half-a-million fraudulent votes available. It has also been reported that about 75 seats in the CA legislature were filled by fraudulent election tactics.
Judges of Elections know the tricks. 75 voters registered at a house that doesn't exist on a non-existent street; another 50 registered at an address that is a gas station ... or an empty lot.