This is a new feature in v1.5 magento. It was not present in the previous edition, so you wouldn’t have put it in your template. Since it’s a new feature and you claim all of your themes are 1.5 compatible, don’t you think you should add it to your themes?
If you don’t feel it’s necessary, that’s fine. But I would greatly appreciate some help in getting it added to my theme as it’s a great feature to have.