Implied warranty of routability?

[Larry Honig]

David Schwartz wrote:
> 
> On Fri, 31 Jan 1997, Larry Honig wrote:
> 
> > Also, for my edification, are there any DOCUMENTED CASES of unroutable
> > addresses being issued?
> 
>         Of course there are. If you go to Internic now and request a /24
> and are issued one, it will be unroutable. Assignment and routability are
> two separate issues. Address being unique on the Internet and address
> being routable on the Internet are different issues.
> 
>         David Schwartz

How about the other case, where there are duplicated addresses? Any
history on this?