Always carry a flashlight on a day hike into wilderness areas when with kids. If lost and forced to stay the night in the wilds, a flashlight can come in handy. There’s no need to carry anything bulky, though. Micro flashlights with xenon bulbs have a battery life of about eight hours and are more than adequate. Make sure the flashlight is waterproof.
Related articles:
g Carry handy carbiners on next day hike with kids
g Do I need to carry rope on a day hike?
Read more about day hiking with children in my guidebook Hikes with Tykes.