with_scope parent doesn't work on pages

[greyskin]

{% with_scope published: true %} works fine - indicating that with_scope does work on page collections.

However, the page parent drop doesn't appear to be accessible. Is it supposed to be?

The following code will print out a link to every page on a site, instead of only pages that are children of the specified parent page:

{% with_scope parent: some_page_slug %}
    {% for page in site.pages %}
        <a href="{% path_to page %}">{{ page.title }}</a>
    {% endfor %}
{% endwith_scope %}