While researching my family tree, I was surprised to learn that my great-grandfather, who I had heard was a soldier during WWI, actually served on the Mexican border. It was an interesting surprise.
My grandfather was in the Texas National Guard and was mobilized in 1916 to serve on the Mexican Border to protect our border from Pancho Villa and over concerns that the Germans would join with the Mexican and invade the U.S. They were demobilized in 1917 and sent home. He had no sooner gotten home before they were mobilized and were sent to France. Many National Guard soldiers had similar experiences.