I agree with some PPs, they likely mean that they will try to co-ordinate babysitting for children of OOT guests, not so much that these kids will be invited as opposed to kids of in-town guests.
But ideally, this info should have been provided on a separate card for OOT guests who have kids, not on the for-all invitation. Otherwise, it could definitely seem as though OOT kids were invited for the entire event (ceremony and reception) whereas kids of in-town guests were excluded, even if they might have been closer (emotionally) for the HC.