Re: Old joke!
Agreed. Postal Votes are where the flaw is, although still quite secure because there are so many people you'd have to pay off.
You can have the Postal Vote scanner just reject the verification form (I think it was called), although the Postal Vote Scanner never actually sees the votes. Again, you'd have to pay off several people in the room. Actually you'd probably have to pay off the whole room including senior management. Everyone being aware if/once caught, they all will get jail time.
Only election staff are allowed in the room. Then you have the people opening the votes. They count those and they go to the postal vote scanner. That person scans in and verifies by eye the scan matches what is in the database and that the scanner software read it correctly. The amount of mums and dads that sign for their kids because the kid is at Uni is mad. Do they really think we won't spot that? Anyway. That is the point you could just reject and those votes wouldn't then be counted. However, it is then up to a deputy returning officer/s to double check that they also agree with your rejections. A senior member of the elections team may also check.
So even Postal Voting is quite secure. Not as secure as it could be, but still not as bad as people think. Blame the public for Postal Votes. It was them that wanted it.
All these people would need to be paid off and you do get serious jail time if caught.