Say you are an honest poll worker. Say, at four in the morning, a "dump" of 30,000 votes comes in. Further say that they are ALL for Joe Biden. Furthermore, there are no votes for down ticket candidates. But you are honest, so, you say, you know, this looks like a highly unlikely occurrence (miraculous might be a more fitting word). So what do you do? An
honest poll worker would say, "they are never going to believe me on this", so you hold off, wait to the light of day, get all of the observers from all parties together, and go through it one by one.
That's what an honest poll worker would do...