This is obviously a tangent, because it is probably impossible today not to be born under some government, but consent consists of staying. If someone in the U.S. doesn't like the taxes, they are free to leave to another nation with lower taxes - but they can't take the land with them, which I suppose throws a wrench in things.

It also gets complicated when people can't realistically leave - they have no money to find lodging or food, they have no transferable skills, they don't speak any other language, they are not mobile, etc.