I also don't think that the world is a more dangerous place these days (apart from the traffic); we just think it is and so if we do allow our kids more 'freedom' than is socially acceptable we're very conscious of being accused of being negligent parents.
You said exactly what I am thinking. It angers me that if I even utter the words "walk to school" people like my in-laws look at me as if I am the worst mother in the world. I do see the dangers with busy streets and the like. But I also see the need for kids to be kids... It is sad really, and when my in-laws have said in the past that it is just too dangerous here, I have actually replied, "well, then we just have to move, don't we?" they didn't like that...

Saša