If a candidate pulled a Studds, it wouldn’t make any difference.
Here in King County, Washington, all voters registered in a precinct are (in theory) in the book at that precinct’s polling place. Anyone who was sent an absentee ballot (close to 80% of voters, right now) is noted in the book.
If a person who was sent an absentee ballot comes in planning to vote, they are given a provisional ballot. These special ballots are put in a security envelope with the voter’s information on the outside, so that the county can make sure they didn’t send in another ballot before it’s counted.
Provisional ballots are also used if someone comes to vote certain they’re in that precinct but for some reason are not in the book.
Because so many county residents are voting absentee anyway, and because it’s cheaper to run an election that way, King County will soon go to all-mail balloting. Supposedly, they’ll be the highest-population county in the US to adopt that so far.
Two years ago, I voted (for federal offices only) by absentee ballot from IL, my state of last residence, over 35 years earlier. I applied for that ballot, as did Mrs. Seldon. To our surprise, without any further application, we both got ballots for the congressional election, which we duly filled in and have returned. I guess in two years, we will get ballots for the four federal offices again. (IL has no senate election this year.) So you can get a ballot without applying, at least in some states. Of course, this came from the county clerk, not from a party.