That's not what they were doing the last election cycle. Absentee ballots are never counted until after the in person registers are in the hands of the board of elections.
What the Obamaites did was have phone banks call up eligable voters and ask if they were registered or intended to. If they said no, a fraudulent registration was entered for them at a false address using a fabricated utility bill or fake ID. Then the fake voter who signed the registration showed up where they wouldn't be recognized and voted the fraudulent ballot. They did this constantly during early voting.
They also called up registered voters to find out if they were still alive, or intended to vote. True the vote stopped a lot of this, by purging rolls.