Hi Martijn,
Thanks a lot for your help!
Your suggestion reminded me to take a closer look at the Selectors API. There I found 'include=hidden', which might be an even better fit for my use case. Using this selector, unpublished pages won't be included.
By the way, do you if there is a way to set all pages that are attached to a certain template to be hidden (or any other status) by default?