Why do married Indian women wear toe rings?

Women wearing toe ring is a symbol that she is married. But, why do women wear a ring on the toe rather than on the ring finger?

Reasons

1. In yester years, wearing a golden ring was common for anybody. Both men and women wore rings both before and after marriage. Wearing golden ornaments was a symbol to show off their wealth and power. For example: A rich man's daughter would wear rings on all her fingers. A man could not easily identify if a women is married or not by just looking at her fingers.
2. Ancient India was a highly disciplned and civilised culture. Men would not "check out" unknown girls unless they are sure that she is not married and available. So they would have to practically look down when they meet an unknown girl. A girl with a ring on the toe can easily signify if she is available or not and help the man to communicate to her.
3. The scientific reason for toe ring is that they press certain nerves in the second toe which keeps the reproductive system healthy and in balance.