crystaltipps. How I agree with you! I thought the OP was maybe thinking of the recent very well covered on TV march about the Brexit situation. That had many children and toddlers in it as shown in the Press etc.
But to make a "one rule fits all" statement is completely impossible and unsuitable as you so clearly said!
I remember when Glenfield Hospital in Leicester was under threat. At our Church one of the children had had his life saved by some heart surgery there. He was a baby. Without that hospital the nearest would have been so far away the family would have had terrible trouble either being with the sick baby or looking after his older brother. So many of us campaigned and children did have banners saying this hospital saved my life.
So that is one example of a good reason to have toddlers with banners.
I do worry about very big marches. However well organised, the fact that they are big and highly publicised can easily lead to crowd problems, even difficulty finding a loo. My friends said it was very difficult getting transport home, even getting back to the station after the last big "People's Vote" march in London. To cope with young children's needs in under these circumstances would be stressful.
So the answer as it nearly always is, becomes "*It depends* upon several factors...."
Angela Rayner lashes out and calls Sunak “pint sized loser”.
Well Labour’s “patriotism” didn’t last very long, did it? 🇬🇧