Maybe there is an inbuilt safety mechanism in these trailers and buggies that I am unaware of or maybe there is a science to the safety of the cage style engineering that I am ignorant about...in which case feel free to educate me....
But I was in South Kensington for work today and on a busy road near the station I saw two bike trailers go by. Each had 3 kids inside. No child in either trailer was wearing a helmet. Neither of the adults were wearing a helmet. These are not quiet roads. Lots of buses and black cabs going by.
If you're taking a child on a busy road in a bike trailer the children at least should be wearing helmets? Yes? No? Am I being overly cautious?