[Groxx]

Because supervisors are never suspect. It's not the machines people worry about, it's the people programming and tending the machines. So to catch a supervisor, you'd need 1-2% of voters to audit the machine... which I find extremely unlikely to ever occur.

[Hellcat]

you seems to be confused about the role of a supervisor. It is the supervisor that is supposed to make sure that the programmers and tenders did not do something improper.