The saying "Don't tread on me" is simply a warning or a statement made to warn someone not to cross your way or to take advantage of you. This saying originates back in the 18th century where it was used as a defiant motto by Colonel Christopher Gadsden. With the saying is a symbol is a symbol of a snake. Most people fear snakes, but many forget that snakes fear people. A snake is not going to bite anyone unless it is messed with and "tread on" so to speak. Check out http://www.humblelibertarian.com/2011/03/dont-tread-on-me-principle-of-peace.html.