> I think a better fix would be to arrange for cron to avoid running jobs
> twice - whenever it sees local time step backwards, it doesn't run
> anything until local time catches up to what it was.

That's not quite right, either.  If I have something scheduled every 5
minutes, I wouldn't want cron to stop running it between 2AM and 2AM.

You might change it to "doesn't run anything which is scheduled more
frequently than one hour", though cron doesn't necessarily know how
frequently something *is* scheduled (especially if the same script is
scheduled several times an hour at irregular intervals using multiple
entries).  You also get to argue over whether *exactly* one hour should
be held up; an argument could be made either way.