I am sure you have all heard by now about the lawyer that is in isolation for an interesting case of T.B. Many people were alarmed that they had to travel with him, and he was out in the community...blah, blah, blah. The thing is though, I work in the health care field and I can tell you that many times, tests are done this week, and two weeks later they inform us that it turns out Mr. whats-his-name in room four 2 weeks ago has something contagious! In the mean time Mr. whats-his-name has been walking around town and being in closed spaces with people. Mr T.B guy was getting married and was around a lot of his family. If he seriously thought he was contagious I think he would be stupid to stay around his new wife and daughter. What a wedding present though! damn! for better or worse...for sure!
You would have though the CDC would have encouraged him to buy and use an airborne mask to decrease passing it on to others. Maybe they did...who knows. Dude says his dad has a recording of the CDC/ doctors telling him he was not contagious before they left for Greece-- well in lawsuitville you have to be prepared for anything!
Any way, my point is you never know who is contagious. Sometimes they know, and other times they don't. So you never know what you can catch from those around you:-)