setuid ignored for root

[utzoo!decvax!ucbvax!unix-wizards]

>From chico!esquire!psl at Berkeley Sat Sep  5 14:13:31 1981
It sounds like we're all agreed that it's an ugly, sometimes dangerous
hack.  The reason I brought it up originally was to find out if anyone
knew of a case where its removal would cause trouble.  So far no one has
mentioned such but I sense the same lurking fear in many of the responses.
Brian Lucas has finally talked Interactive Systems into making a mod in their
systems (for unrelated reasons) which makes the permissions associated with
a process be the union on the permissions held by the effective and real
uids.  This change certainly sounds reasonable and if no one can find a
hidden pitfall would be the perfect companion to the removal of the ignored
setuid for root processes...

Pitfalls?