Originally Posted by
chaadster
I didn't bother with a helmet for the kids while in the trailer until around 18-20 months, both because of concerns with neck strain and difficult fitting, but also because it was very hard for me to imagine a scenario where they might hurt their head; falling branches, maybe? There are no rockslides in my area.
The scenarios are pretty far, but I'd figure the biggest threats to a trailer would be car hits or overturning.