By whom? Overseen by whom? Who oversees the overseers? Not to mention people make mistakes, ballots get dumped, and nobody has any evidence their vote was actually counted.
Here's a long but fascinating tech talk on a real solution:
I can talk about Ireland, as I've been an election observer there. The way we do it is that ballot boxes are locked and sealed with tamper-evident seals after a polling station has closed. Elections observers; including representatives from the political parties may request to add their own seals. In some particularly contentious districts this is done, but for the most part people are happy with the official seals.
The ballot boxes are then transported by the police force to the nearest "count center". The next morning, the seals are inspected and those ballot boxes are opened. All of the ballot boxes in a constituency are counted together in a secure, but open area. Here's a flickr set with a good number of photos showing how it's done:
the counters are within the fenced area, and the observers - including many people from the political parties, surround the fence. The entire process is easy to see.
One particularly important part is what happens when the boxes are opened. The contents are just dumped out on the table and one by one each vote is turned to face up and towards the observers. The observers then "tally" the votes and mark which candidate (or referendum choice) the voter marked as their first preference.
All parties participate in this tally and it provides the first take on what the result will be. The margin of error on the tally is < 1%. Some tallies with enough tally-takers also count the 2nd and 3rd preferences, but most tallies just project the transfers (we use a transfer based voting system) and that too is generally accurate.
Contentious votes with identifying or ambiguous marks and so on are kept aside and argued over by people like me for an hour or so, but they never make much of a difference.
The end result is a process is very verifiable and auditable, in easy-to-understand human ways; you can literally show up at a count center and count the votes yourself as they come out of the boxes, and make sure that you're not being duped. That's a nice accessibility property too.
Rather than a police force transporting a sealed box, a commercial courier company or volunteer with their own car moved what might not have even looked like an official box (perhaps a printing firm's box) which in the end might have been thrown out in the recycling or might have been maliciously removed as the warehouse doors were left open or when a single security guard was on duty overnight.
As Mr Keelty wrote: "There is less concern for the security and integrity of Senate ballots because it is considered that they have less of an impact on the election outcome and in any event are warehoused for six years. This is a cultural problem within the AEC and it needs to be addressed.
The fact that it had been thirty years since the last full recount of Senate ballots most likely added to the loss of care in routinely dealing with those ballots during the election."
I appreciate the thorough response and it does sound better than what I had envisaged.
However, there is still no way for me as an individual to know for certain that my vote has been counted. The best I can do is trust in the physical security practices surrounding the ballot box and the honesty of the volunteers involved. And even with a margin of error of < 1%, elections have been decided by fewer votes than that (~15 votes in my riding in Waterloo, ON in a recent election) and recounts are expensive, slow, and contentious.
I encourage you to watch the tech talk when you have a spare hour. We have the technology to create a much better and more transparent system.
We don't. I remind every group that tries to automate voting in my province that on election day somebody is going to denial of service the system to use it as an attention seeking platform which will just force a physical vote anyways. Other ideas floated like blockchain decentralized voting are also impossible since none of us can run a trusted personal device to vote with, and plenty of voters have no access or don't want access to phones or any other devices. Worse, every couple of elections there's some sort of scandal where a foreign "politically exposed person" has been caught propping up local candidates or outright fielding their own puppet to seemingly unimportant elections like the parks board so they can reap real estate or resource mining benefits. Imagine what kind of havoc a foreign state could wreak on an electronic voting scheme.
Full, transparency across time makes it easy to buy people's votes, or punish people for voting the wrong way. The moment I can check that my vote was counted, and was counted accurately, then my boss/landlord/wife/friend could pressure me into showing them said record.
The fact that I can vote very differently from what is socially acceptable in my social group, and there is no way for them to know is a feature, not a bug.
In Australia, they're counted by an government official, and overseen by mutually hostile volunteers (scrutineers) supplied from the major parties. It's boring to be a scrutineer, but it's in the major party interests to ensure they are sent.
By whom? Overseen by whom? Who oversees the overseers? Not to mention people make mistakes, ballots get dumped, and nobody has any evidence their vote was actually counted.
Here's a long but fascinating tech talk on a real solution:
https://www.youtube.com/watch?v=ZDnShu5V99s