Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> writes:
> The fact that different versions of PostgreSQL get it right or
> wrong in a variety of ways indicates that the logic may need
> to be fixed but does show that in principle it is quite
> possible.
7.1's version of AT TIME ZONE was so badly broken that it doesn't really
matter whether it accidentally failed to malfunction in your particular
test case. That's simply not relevant to later versions.
regards, tom lane