Who Was "Lawless Mary"?

While doing some research today, I came across an intriguing name in a 1940 census: Lawless Mary. She was an 82 year old widow living in Texas, and I had to learn more about her. What fascinating life did she live to earn her nickname?

After finding her in a 1900 census, it turns out "Lawless Mary" was not a nickname; her name was Mary Lawless. 

1940 U.S. Census, Falls County, Texas, Lott Ward, population schedule, page 7B [written], household #165, North 6 St, John Priest Household, image, Ancestry.com (http://www.ancestry.com : accessed 15 January 2016), citing National Archives microfilm T627, roll 4030.

The 1940 census enumerator had just added a line indicating her surname was the same as the name abover her: Cone. But, her name was, in fact, Mary Lawless and there is not an amazing story.

So, if you were researching Mary Lawless, how would you have found her? I think the most likely way would have been to search for her daughter, Susie, in the census.