So we moved from the city to the burbs a little over a year ago. We live on a very small cul de sac. There are two corner houses whose backyards face the cul de sac (their front door is on a different street), and then three houses, including ours, in the actual circle. Kids live in each of the two houses on the corner. In one of them the kids are now 6 and 4, so they were 5 and 3 when we moved in.
A few months after we moved here, the kids got to know each other and started going back and forth to each other's houses. I always made sure my younger ds was with his big brother, and they always went in to the neighbor's backgate, which was in the cul de sac, and I can see and hear from my house. So one day the other two boys ran over here and were playing downstairs. The younger one yelled out to me that he was going home, and he walked out. I'll admit that it didn't really occur to me that he was only 3yo, and I was very new to the whole cul de sac, suburban, in and out of the house thing.
A few months later at a gathering, the mom mentions to me that she was in her backyard, heard her kid say he was coming home, and then waited a second before coming out to see where he was, and he was walking out of the cul de sac down to the main street. (It's not a super busy street, but still not where you want a young child wandering around.)
I was horrified. It never occured to me that he wouldn't have gone home, and it was at that moment that I realized how young he was. I was so completely mortified that I hadn't watched him go home, or done something else to make sure he was safe. Since then, whenever the kids come over, one of the parents is there as well. I don't mind this, and I understand that they feel like they need to be watching what is going on because I can't be trusted.
However, because they feel like one of them must always be here, there are a lot of times my kids want to play that they have to say no because they are busy with something. So I kind of want to say something to them to reassure them that I am not some kind of irresponsible space case, but I also don't want to open some can of worms and put them in an awkward spot. So, what would you do? Just let it go, or try to talk to them about it? We see them often and are very friendly.