I have seen a couple of shop keepers (in small - mid sized shops) in Hong Kong counting some routine things with this character : "正". The actual tally would start off with the first stoke of that character and increase by 1 according to the stroke order of the character. So, one 正would effectively represent 5 people.
I believe the Western tally also counts to a maximum of 5 per tally.
I'd like to know why that particular character is used. (I have seen it used in stamps before too).