What is broadcasting then mate?
If someone's reading a book next to you on a plane, you can barely avoid noticing what they're reading. Or if they're playing Cow Clicker+++ then you will spot that too. Why on earth would anyone think that they can send texts sat next to someone without them seeing what you're writing? Would you do it at work and assume you can **** your boss off when he's next to you?
No thats just being nosy.
Would you assume you could sit there reading your bosses emails just because he is sat next to you?