Personal choice for sure. Ive made mine....I have no problems with my kids on my bike. Rain or shine.....around the block or on a week long trip.
Maybe its the fact I live in a farm community where everyones kids ride dirt bikes and atvs.....maybe its "little town" syndrome.....but I never get any flak about it. In fact I get alot of smiling and waving.
My kids were "riders" long before I was. They had ATVs and dirt bikes 2 years before I owned a motorcycle (or my own ATV for that matter).
They ride almost daily in the yard. Im not a HUGE stickler on safety gear in the yard. Yes I know you CAN be killed hitting the ground at a mere 10mph in the soft grass of a yard. Its all about acceptable risk. My sons on a larger ATV (10 year old riding a Honda TRX250) so I require he wear a helmet even when moving it around. Its heavier....its faster. When he rides his TTR90 if he forgets his helmet I dont make a big deal about it. My daughter (5 years old) moved up from her Kazuma 50 (pink ATV in the pictures) to a Suzuki LT80. Shes getting the same treatment.....she MUST wear a helmet when riding it. For a 5 year old its a faster, bigger machine.
When we ride anywhere but on flat level ground in our yard - helmet use is required - no matter what the machine. In the yard.....on the smaller machines that arent capable of faster speeds - Im not that concerned.
My kids dont wear helmets when riding bicycles.
They absolutely, positively wear helmets when riding on the street with me now. Before, I made an exception for my daughter. She was small enough that even the smallest helmet was very large and heavy for her. She had trouble holding it up. I was MORE concerned she would break her neck wearing the helmet then I was of injuring her in an accident. So she did not wear a helmet. Now that she older....helmet all the time.