I was. But our block got turned into a ghetto in the 15 years we've been living there, so we lock the doors now. I always used to go to my friend's house down the street after I did my homework (more often than not WITHOUT doing my work), and no problem. Today, though I wouldn't be surprised if my parents made me stay at work with them if I was 8. My neighborhood has become "tha hood."
The kids I used to babysit for were an 11 and 9 year old boy in one family, and an 11 year old boy and 7 year old girl in another family. The first family lived out in a rural town just outside San Angelo (which is really freaking small itself), and they still wanted a babysitter. I guess it's just up to the parents' discretion. I wouldn't look down on it, I'd probably let my kids take care of themselves and their younger siblings at about 10, depending on their maturity.