I’m sorry, but letting 3, 4, or 5 year old kids run around in front of your house, unsupervised, with the street right there is not safe. I do not trust a 3 or a 5 year old not to run out in front of cars passing by. I do not trust my kids lives with the drivers in my neighborhood.
Many times I have narrowly missed an unsupervised toddler(s) who runs out into the street in front of me (and I drive under the speed limit in neighborhoods for this reason). A three year old kid or even a 5 yr old does not think about on coming cars when they are chasing a ball or just chasing each other.
Also, I’ve seen a ten yr old going around and opening up people’s mail boxes. When I’ve said something, I get the “mind your own business” and “how dare you correct my kid” speech.
I know that you are not defending that, but sometimes kids DO need supervision.
If you are talking about your backyard or a neighbor’s backyard (that you know) then fine. Older kids who have been taught how to watch for traffic, fine. If you know your neighbors well enough to trust them - great.
But, I’m not willing to trust everyone to be good drivers or moral and non-perverts.
They don't play in the streets. They play in the many undeveloped lots surrounding our home, where they climb on the sand hills and mountains of dirt, the same things I used to do when I was five and growing up in a developing subdivision.