[tz] Rules for TZ+ database

[Paul Eggert]

Stephen Colebourne wrote:
> most end consumers of the data cannot tell the
> difference between a Link and a Zone. As such, from their perspective
> it is very odd to find that some IDs are allowed pre-1970 data and
> others are not

If we're talking about the perspective of most end consumers,
most of them don't know or care about pre-1970 data.
So they won't find anything odd at all.

> had someone provided detailed pre-1970 data for
> America/Aruba a year ago, I think you would have accepted it

No, we've excluded similar pre-1970 data in the past, e.g.,
Europe/Zagreb.