Would you want everyone knowing everything that you thought? Including sexual things? Bad things you think about other people? Weird random subconsious things that everyone thinks? Trust me, it's scary. You're just sitting there, then everyone starts talking about what you just thought.
In this scenario Ninja, it is more likely that you have picked up on the conversation starter thought before the conversation started.
When it comes to sexual thoughts and 'bad' things you may think, I do similar to what Flame has said, which is what I was saying in my first post about being vigilant with our thoughts.