In unix, I know that you have to be a member of a group to change the group owner of a file to that group even if you own it, but can someone please tell me why. I don't understand why you shouldn't be able to change which group has  special access privileges of your file if that group isn't one your a member of.
Why do you have to be a member of a group to make that group the group owner of your file?
group;chown