On Star Trek: The Next Generation, counselor Deanna Troi can sense emotions from people on other ships or planets which are in contact with the ship. It always seemed to me that visual contact (and maybe a little cold reading?), emotional strength and/or power of the given entity, allowed her to sort the distance when reading emotions from people on screen, and that she needed some physical proximity to sense other beings, like when she senses the emotions of the ship's population, in a moment of danger. But in the Episode The Royale, she can -from the comfort of her chair- focus on Riker alone (who is stranded on a planet below), while the rest of the crew is trying to get through the interference just to get a reading on the away team's whereabouts. Though I don't remember her sensing a nearby cloaked ship, such ability could be a very useful asset in battle.
Is there a way to limit her ability and make a shielding device that she cannot pierce?