How would you distinguish honest errors from malicious vandalism, especially with reagrd to something like dates? I could edit an article to reflect that World War 2 ended in 1935, without intending to do so because of a typographical error? Unless the edit is obvious vandalism, (like saying World War 2 ended in 2045-which cannot, reasonably, be termed a typograhical error), it would be difficult to seperate the vandals from those who make such errors while typing or as a result of looking up the date from a source that is not correct.