All summer I have seen mum's striding along (often with sunglasses themselves) and their poor dc with their heads turned to one side or even hands in front of face desperately trying to avoid the sun's glare. Some of the babies are even in rearfacing pushchairs still so the mums must know that the sun is in their dc's eyes.
Even if they can't afford a proper sunshade I don't know why they don't get a muslin and clothes pegs to try and improvise something.