Never!
I do add the leading zeroes, mostly because the only time I write dates is for people to copy type onto computers. The number of times I've seen people botch data entry because they're stupid is unbelievable. The leading zeroes make it far harder to misinterpret the date.

But yes, the sign thing is daft. I have yet to see it in real life.

EDIT: A thought occurs; if the petrol stations have cheap signs (which is likely, as they would have had to upgrade quickly when an extra digit was added), they might need a place holder to stop the useful digits flapping about if they're not held in place properly. They could, of course, just use a blank one.
(ThomsonsPier consumes, Tue 4 Nov 2008, 11:59, Reply)