Implied license

At common law the owner was required to confine his live stock, or else was held liable for any damage done by them upon the land of third persons. That law was not adapted to the situation of those states where there were great plains and vast tracts of uninclosed land, suitable for pasture. And so, without passing a statute, or taking any affirmative action on the subject, the United States suffered its public domain to be used for such purposes. There thus grew up a sort of implied license that these lands, thus left open, might be used so long as the government did not cancel its tacit consent.