I would think so. Mail in ballots are a treasure chest for fraudsters. So are the weeks of voting.
Fraudsters have been successful at making the ballot of the registered Election Day voter canceled.
Precincts are neighborhood voting locations. The neighborhood workers sense what is going on when this happens. In blue states it takes only a few who are evidently in on it.
In Red states and Purple states, it only takes the one county that holds the biggest city, which is almost always Democratically controlled, to facilitate the mail-in fraud and win the state for the Dems.
Wayne County (Detroit) in Michigan, Maricopa County (Phoenix) in Arizona, Philadelphia County (Philly) in Pennsylvania, etc.