We take safety pretty seriously in our house and I use any opportunity that I can to teach these lessons to our kids. It is the way it was for me growing up and so it is for my children. For example, my husband and I and anyone else who rides in our car always wears a seat belt. Our children ride in the appropriate car seats/boosters for their height and weight. When I ride my bike I always wear a helmet, even if it is just down the street or around the block as does my husband. Likewise we make our kids wear their helmets even if just riding their scooters or bikes in our driveway or along the sidewalk in front of our house. It is habit and both know it is an expectation, a non-negotiable. They know no other option will fly. We don't let our kids play in the street but apparently we are one of the few as it seems most of our neighbors view the street as their personal playground that does not require caution or supervision. I also know that others don't take the same precautions when it comes to safety and while I cringe at what I perceive to be their irresponsibility it is not my place to interfere in other people's parenting, or lack thereof.
My daughter, on the other hand, has no qualms about pointing out the error of other's ways. She has not quite mastered the filter yet between what she thinks and what she says. We have a lot of kids who ride their bikes in the late afternoon and early evenings, usually at the same time I am outside with my children. Each time a child, usually helmet-less, rides by my daughter says in an extremely loud voice, "He should not be riding in the street." Or, "She should be wearing a helmet. She could fall and be dead." And she's relentless. She says it over and over and over again until I agree and repeat verbatim what she has just said. A simple, "Okay baby" will not suffice. She wants me to make sure that I know she knows that what they are doing is not what I allow. For that I am proud. However, I also don't want her to be the kid that no one will play with because she tattles on everyone.
So, we are working on that balance. When she asks why those kids don't wear helmets and those kids play in the street it takes every ounce of self-restraint to not answer with, "Because sweetheart their parents are idiots and don't care enough to take proper precautions. These are the same parents that then freak out and sue everyone and their mother when their child does get hurt when really it is their own fault. That is why." However, I instead give her some version of "Each family has different rules and mommy and daddy make rules for you and your brother that we think will help keep you safe because we love you." Isn't that big of me? :)