What IF: time travel

People say you cant go back in time because if you can then we would see space travelers traveling back in time to visit us. Well... what if.. WHAT IF: we didn't travel back to the past because we didn't want to change the past which would later change the future. So in the future the scientists mke an agreement that they'll never travel into the past because they do not want to disturb anything.

If time travel was possible, any dumbass who just went back in time probably died unless the exact position of the earth was determined before the time jump was made. In essence, the only real places where you can travel in time are the periods of time where the earth's current position.

If you're so much as off by a fraction you'll end up with a foot in the ground or even worse. My idea is eventually we'll master time travel, but at that point we will have stopped caring so much about it.