I haven't seen the footage but I do think it's a bit of a silly thing to do, as we have no idea whether or not they are trying or having problems if they are. If she was pregnant, then it could be a sweet gesture.
I do think that they will try, as it would be unusual for the second in line not to. I would think discussions re does she want kids would have taken place before marriage as, frankly, for the wife of the heirs, it's their job to have children, whether we like the idea or not (I am anti royalist so hope they all die out eventually).
On a different note, I'm surprised Zara has change her name. I was shocked to read that she is formally known as Mrs. Michael Tindall 
I'm guessing if she did hold a royal title, Princess whatever, she wouldn't be known as that but as she holds no title, she's known by her husband's name despite him being a commoner? What would happen if she wanted to use the title Ms?
What a load of shite, though, to be known by your husband's name not your own. I'm also surprised that she was referred to as Zara Phillips at the Olympics as they were very big on formality. Tina Cook, or example, is usually called that but they insisted on using her full name, Kristina, for the Olympics.
Did she change her name or not? I wonder if she didn't but court formality calls for her to be known in an old fashioned way? Thinking out loud, now.