Of course nobody can prove it. The rules are setup to be so loose that there is no way to prove any fraud. As I said below, registering to vote as an entirely fictional person is absurdly easy in many jurisdictions. In California, for instance, one can skip any identity checks by simply marking two checkboxes: one indicating they have no ID, and one indicating they have no social security number [1]. Voila - in under 2 minutes, you have invented a brand new, registered California voter. Combine this absurdity with automatically sent out mail-in ballots in many states, and you have a disaster waiting to happen.
You're forgetting something. If someone were to check the existence of the identities, they would eventually show up as fraudulent. Here, the "proof" works by absence (which is admittedly not logically correct according to the strict classical rules).¹
Consider that an investigation (that includes said identity check), concluding with a recount happens
• mandatory by design to a random small subset of voting districts
• everytime someone reports to the voting commission an indication or outright evidence of irregularities or fraud
• everytime there is a difference between head-to-head candidates smaller than a certain percentage
If GP is right and "nothing pans out", then that means that the CA Secretary of State web site is not an effective tool to commit voting fraud.
¹ A common analogue is: "I do not believe in gods. Theists can change my mind when they bring forth evidence that measures up to the extraordinary claim. In the last couple of thousands of years, this did not happen. Thus, I will live my life as if gods do not exist."
Absence from where? It is perfectly legal to not have an ID or social security number. Not having those things proves nothing. And nobody is going to track down everyone in the country with the same name and DOB that you selected and ask them if they are the Fred Wilson (example) that voted in California. People move all the time, so it wouldn’t be unusual if they went by the house and that person doesn’t live there.
The way that system is setup to accept voters without ID verification, there is not a way to legally disprove that the person with whatever name and DOB chosen does not exist (assuming more than 1 other person in the country shares those characteristics). Hence it would be impossible to legally prove that this invented person isn’t real.
Exceptional claims require exceptional proof. Being able to file one fake account vs 10,000 (and not get caught) to throw an election is about the level of proof you'll need and no one has ever come up with that level of proof. Until then people claiming mail fraud are just shouting into the hurricane of the rights of individuals to not be disenfranchised.
I literally just showed how shockingly easy it is for anyone to invent California voters in a matter of seconds. That’s exceptional in my opinion. I could write a script that would register 10k of those in several minutes. But the more likely scenario is that I can’t be the only one that has realized this...nobody knows how many people are doing this once or a few times.
That is the whole point of this conversation - the possibility of incredibly easy, undetectable fraud renders all votes meaningless because we simply don’t know how much occurred and there is no way to find out because the rules are so loose. Until they are changed, it completely negates any point in voting.
[1] https://covr.sos.ca.gov/