I suspect that whoever prepared the legitimate mailed ballots did so in a very organized fashion. That means the ballots were likely sent out in blocks, and payment to the post office would likely have been made through special accounts.
Illegitimate ballots were likely NOT prepared in official governments, and would have had postage paid by outside sources.
If some state officially paid for 500,000 mail-in ballots to be mailed, and 550,000 mail-in ballots were received, then we know two things.
First, 50k ballots are illegitimate, and second, someone paid for those 50k ballots to be mailed, and those funds might be traceable through post office records.
I have zero idea how useful this line of investigation might be, but remember... Catching criminals frequently means following the money, and this is a money trail I have not heard anyone talking about.
I now leave this in the hands of whoever thinks they can make use of the idea, you glorious, deplorable autists.
I dont think it is a matter of the ballots themselves. The ballots being cast are real. It's just that the people completing them are forging names, harvesting, etc.
Watermarks and payment tracking doesn't tell you if the vote was from a dead person, a nursing home resident with dementia, or from a eligible voter that was duplicated in the registry.
I could be in there twice... once with my real birthday amd once with a birth year of 1900. They complete another ballot for me under my other registration.
Remember though that at some point, your fake second ballot with a 1900 birthday had to be filled out by someone. Think about how hard that would be to organize if they were attempting to steal ballots out of mailboxes, and then put them back in mailboxes...
The post office uses machines to track mail movement. Even if the money angle is too hard to crack, I suspect the post office keeps data records of what mail goes where. If a state elections organization claims they sent 550,000 ballots to citizens, but the post office only has records of 500,000 being received by the post office,and delivered, then there is a problem.
Money is not the only thing the Post Office should be able to audit.
Mail-in ballots on this scale have never been seen before. If there was large scale mail fraud, I strongly suspect that some evidence of wrongdoing could come from the Post Office.
Here's how I think it works:
Let's say I never vote. They search voter roles and identify me. They then create a duolicatw registration with a birth year of 1900. After polls close, they go through to find all the 1900 birthdays. They find that I didnt vote. They complete a ballot under my name (with the correct birth year). The 1900 birthdate is just a way to "flag" and easily spot the non-voter duplicates so they can check to see if they actually voted.
That would lead to two potential auditable data sets.
If the ballot is postmarked as having been delivered, then the USPS computerized mail sorting machines should have a record of it being sorted, and which machines processed it. If they find strangely large numbers of ballots coming from certain post offices, that might lead to actionable investigations.
The states buy those ballots from somewhere. If the state sends a ballot to you in the mail, then some cheating Dem uses another ballot to generate a fake vote, they have used two ballots. Do that 10,000 times, and it becomes a statistical anomoly if an audit is performed on ballots. If they are using fake ballots, that should be detectable. If non-state entities are buying official state ballots, that might lead to interesting places too.
Most nail is bar coded and scanned by the PO when received and delivered. Were the ballots Bar coded. Also the PO photographs and scans mail so the recipient can see what is coming in their days mail.