Are there really states where you don't have to sign ANYTHING when you go to vote? Is Washington one of them?
Here in Alabama, I first have to check in with the sweet old ladies manning the computer lists. They check my name off after I give them my address AND approved I.D. I don't sign anything at this point. Now I can enter the voting station.
I then choose a voting machine. There are one or two poll workers at each machine. Just before I enter the booth, they have me sign the book that goes with that machine. The signature book is sequentially numbered.
As a Republican observer, I've watched the end of day routine. At closing time, they check the total votes on each machine against the number of signatures in its companion book. They MUST match. In the rare case of a discrepancy, all heck breaks loose. Police are on hand and they immediately impound the machine & the book, guarding them until election officials and party reps arrive. Yes, there have been glitches, but the record keeping makes it possible to correct them.
Seems like a pretty good system to me. Given that every MACHINE is balanced at day's end, it would be very difficult to "discover" votes later in the process.