[patall]

As I know it, you have 2-3 persons that count together one urn. That's not one person doing it. And you can do recounts. And adding large numbers of ballot papers is not easy because its marked how many there are in a ballot. (What is more effective is declaring a number of ballots invalid if they are not the right candidate but still, we are speaking about in extrem cases 100 votes, not possibly millions as would be possible in hacking an electronic voting machine)