[tz] data not represented in tzfiles

[random832 at fastmail.us]

On Fri, Sep 6, 2013, at 11:38, Zefram wrote:
> You misunderstand it.  The situation of concern is where the 400 year
> period governed by a rule is immediately preceded by something that is
> *different from* what the rule would have.  If the preceding DST
> behaviour
> has transitions later in the year than the transitions produced by the
> rule, the last preceding transitions could occur less than 400 years
> before the last rule-generated transition that zic puts in the output.

Why not put a non-transition (i.e. a transition to the same offset
already in effect) at the beginning and end of the 400 year period?