People who may know them have more context and might recognise them, yes. If I'm on a flight from Amsterdam to London and I'm complaining to a friend about my boss, someone livetweeting my hilarious rant might keep me pretty unidentifiable by just using my first name.
But my boss probably knows I was on a flight from Amsterdam to London that day (as I asked him for permission to take the time off) and based on the rant will probably know it's me, talking about him. That could have some pretty serious consequences. Of course, maybe I shouldn't complain about work in public, but would you honestly want to live in a world where you couldn't?