Most warning signs regarding a double spread (or objects overlapping/ near mid) page have to do with the image going over the middle of the page, It's not an issue of course, the software simply brings it up to remind you to take care that no critical information is lost right in the middle, So no one's face is exactly on the spine line, or no text goes across there.

It's just a mechanism to get you to double check yourself, it is always best to go through your work via the preview mode prior to ordering, if you are happy with what you see there you will most likely be happy with the final result.