Which is why the voting machine should print a paper receipt which in plain text tells what vote you cast; this receipt is then deposited in a ballot box.
If a result is disputed, simply count the paper ballots like we do today.
Unless the result is contested you have saved an amount of counting effort which could be a cost saving. Though I suspect it would take some time for the ROI of implementing such a system to work out positive.
> > Unless the result is contested
> > you have saved an amount of counting effort
> The ballots are already optically scanned.
If the result is contested then I presume that this scanning may also be under suspicion (of being faulty or having been somehow doctored deliberately).
> > cost savings
> A handful of pencils per-voting-booth is far cheaper than any computer+printer solution.
Why is why I mentioned the time for ROI to become positive. The electronic counting will save time (man power for the initial count, the need for recounts, and just wall-clock time so the results are available earlier) but the cost will be high. At some point perhaps the solution will pay for itself in time/resources saved but it will take quite a while if at all.
Maybe you should study how elections are actually implemented instead of making assumptions. I suggest watching the talk I linked to in my top-level post.
> this scanning may also be under suspicion
Obviously. Hence why it's important to recount the paper ballots by hand. This is also why about half of the states require confirming the reliability of the optical scanners with a random sampling of hand counts.
> At some point perhaps the solution will pay for itself
No, it won't. Computers per-voting-booth are always going to be a lot more expensive than an optical scan tabulator per-site.
Also, because a computer+printer solution involves a lot more devices, you will need a larger amount of testing by hand recount. You are increasing the workload.
And since you can't know that the computer actually recorded what was printed on your paper receipt you have to dispute the result by default if a good democratic process is important to you.
So if you have to count the paper balloty anyway, why even bother with spending all that money for a voting machine?
There's at least two reasons, possibly even three:
a) Unless the outcome balances on a handful of votes, chances are noone will contest it. (If the result shows 47% to Party A, 32% to Party B and 21% to Party C, whereas polls showed 46% to Party A, 33% to Party B and 21% to Party C, chances are the result is fair.
That being said, yes - I think it would be good if just about anyone could contest the result and have a recount done - at least if they had to foot part of the bill, so that not every curmudgeon in the Kingdom would claim recounts just for the hell of it.
b) A voting machine system would enable one to have a preliminary result ready in seconds after ballot stations close, rather than today's system where, based on the size of electoral districts, results may be delayed by several days.
c) If properly designed, a voting machine could assist the user in creating a valid ballot; I've volunteered as an electoral clerk several times - we have had to dismiss surprisingly many ballots as there is simply no (approved) way to determine voter intent. A few checks before the vote is cast would likely improve matters.
If a result is disputed, simply count the paper ballots like we do today.