setuid not working if user is root

[utzoo!decvax!ucbvax!unix-wizards]

>From IngVAX.eric at Berkeley Tue Sep  1 12:10:20 1981
I must also cast my vote for this feature as being misguided,
and removable.  As a measure of this, consider how many people
didn't even know the feature existed!  It seems to have no
redeeming social value, and only causes problems (in fact, I
am surprised that INGRES has never had problems with it, since
it runs setuid to "ingres" -- and creates files mode 600 --
imagine the trauma if root creates a relation!).

I assume the purpose of this (mis)feature was that setuid was
supposed to add priviliges, as proposed earlier -- and so this
feature made UNIX seem to have something like "rings", and
setuid would only add permissions, never remove them.  I contend
this is an incorrect view of reality.

eric