Final answer:
The nickname given to people who snuck onto land to claim it early is "Sooners." These individuals would illegally enter the territory before it was officially open for settlement, gaining an unfair advantage over others.
Step-by-step explanation:
The nickname given to people who snuck onto land to claim it early is "Sooners." During the land rush in the late 19th century, some individuals would illegally enter the territory before it was officially open for settlement, thereby getting an unfair advantage over others. These individuals were known as Sooners, and they often used weapons and violence to defend their claims. The nickname originated in Oklahoma during the Homestead Act and has since become synonymous with those who exploit loopholes and act in an opportunistic manner.