I voted yes, all the time. But of course I have some exceptions.
We all wear helmets on bikes, all the time, outside our garden (yard). It's the law for everybody here & I won't risk the $120 per person fine. Besides, it's just sensible with the way some people drive cars.
The kids also have to wear helmets when they ride scooters outside the yard, but not inside the yard on the little patch of cement we have under the pergola. THey don't have to wear helmets inside the yard when they ride bikes, except when they are using the bike jump. I do insist that they put a helmet on then, because there is the possibility that they could fly off the bike & into the rock borders of the garden beds or a fence post.
eta: my kids also do a lot of things that others might consider crazy & unsafe- like jumping off waterfalls into creeks & swimming in huge deep rivers, & boogie boarding in the ocean on a rough day, & rock climbing (bouldering) 3 meters above the ground without ropes, & hiking through the bush in snake country, & being caught out in a thunderstorm on a mountain peak (that scared me too, tbh, but I had to go with the moment & be brave, you know? No point in the kids being freaked out too...)