Wireless Signals Bounce off Paint

Yes, technically it is possible to create a special paint that can bounce "unwanted" wireless signals of the walls that the paint is applied to. Or so the article says. But it stands to reason to be possible. I question, the "unwanted" part of it. It sounds to me like it will bounce "all" the signals off the painted walls. Does that mean if you paint the inside of the building, wireless signals won't 'bleed' outside? Aside from special security spaces, this might be a solution for those who insist on talking in movie theaters, concert halls, etc. Read the full article here and decide for yourself!