The American military dropped many leaflets warning the Japanese population to evacuate their cities or face bombing. They did not specify the exact targets and when they would be bombed, or the type of bombing to be expected.

However, the leaflets you link were dropped after the bomb was dropped. There was no prior warning of the atomic bombing.

Japanese civilians who read the leaflets didn't really have a lot of options. Their jobs and homes were in the city. There were not millions of empty houses in the countryside waiting to accommodate them. And unarmed ordinary civilians were not in a position to rise up and protest against the military authorities.