I believe you are correct like NSA and phone calls - key words like stuff you can't say at the airport.
In the 1990's, there was a great deal of hubbub about Carnivore and the like. Folks used to have signatures for their email peppered with words like hijack, Bin Laden, terrorist, and the like. The black helicopters never came.
Does the capacity to monitor an individual's communications exist? Yes. Does the capacity to monitor everything, all the time exist? No. It has to be directed. That's why I'm not worried, because...
Wait a minute. There's some guys knocking on my door...