Had those cities been there she could have run. In these last days when terrorism is so rampant and some governments offer so little protection, maybe these cities of refuge need to be built everywhere. God provided a place of safety in Bible times to eliminate mob vengeance. Our God believes that we are innocent until proven guilty. Our western legal system finds its foundations in this Biblical base.
Axe heads fly off just like people, fly off the handle.
The Israelite family could not sue the axe company for making a shoddy product because there were no attorneys in those days. But they could take out personal revenge on the man who was cutting the tree down, but only if they could out-run him. He must flee quickly to the nearest city of refuge. Probably today we would sue the axe company. But they didn't have any attorneys, bless their hearts.