Right. We already draw lines. The following wouldn't be a strong argument for removing the laws against robbery: What if I accidentally get accused of robbery

Right. We already draw lines. The following wouldn't be a strong argument for removing the laws against robbery: What if I accidentally get accused of robbery because I pick up someone's belonging to return it to them when they had left it somewhere. I would rather have robbery laws and deal with these cases as they arise than not have robbery laws at all. Same goes for harrasment.