I ordered both because Bimmer told me too
But seriously, Bimmer makes a good point and the baby comes first. Also, I don't want my mrs buying some Bart Simpson sun blinds and installing them in my (I mean our!) new X3!
Oh, and I ordered the UV band on the windscreen too (part of climate comfort package). I only went for this because I had ordered everything else in that package separately (sunroof too) so it made sense (I think!).