"Reviewer" gets Admin-like rights?

Hello,

As soon as I make a user a “Reviewer for” a given department suddenly they have all permissions to all files assigned to that department even though:

  1. Their user & their own department permissions are not set in that way (they should not be able to delete, check out, change permissions, but they can).
  2. They are members of a different department.

Any help would be greatly appreciated. In this way I am not able to setup a real review system since doing so is giving the users rights to delete or modify existing files.