There is a moral issue as well. In addition to just hearing the thoughts broadcast by others, you will also develop the skill to reach into their minds and read their secret thoughts. We can't do that! It's wrong, but it's hard to resist. When a cute boy is looking at you and you want to know what he's thinking you have to respect his privacy, and not read his mind. You will especially want to avoid any images you might find in his mind, they could be shockingly pornographic.