Waukesha County Clerk Kathy Nickolaus, she of the 7,500-vote miracle, also knows about operator error, somehow distinguished from human error:
A push of the wrong computer key resulted in all votes being counted twice in Tuesday's Assembly District 33 primary, but the mistake did not change the outcome of the race, Waukesha County Clerk Kathy Nickolaus said Wednesday.
...
After the votes were canvassed Wednesday afternoon, Nickolaus described the mistake as an operator error. She said that a worker "hit the wrong button." The error was discovered after one of the town clerks called and pointed out that the numbers listed on the county Web site appeared to be greater than actual turnout, Nickolaus said.
[Milwaukee Journal Sentinel, 12/15/2005]