I am reading a book at the moment where an assassin has killed two people (politicians) and is now trying to make his way to New Orleans by train, to live in obscurity, thinking "there is plenty of work there after Hurricane Katrina has messed up the place", and the last two books (both American books) had similar scenarios of people being asked "show me some ID" and in one case being shouted at "ID! Now", completely randomly. Anyway, in the book I mentioned, the character (hero of the book) has ID demanded from him from the conductor of the train after he is involved in breaking up a fight on the train (he offers to get off the train at the next stop if the conductor will "waive" his "right" to have ID shown). At the beginning of the book he had ID demanded by the police when he was walking along a country road (he got out of this one by pretending to be mentally retarded and not able to talk).
I know that these books are works of fiction but don't (presumably anyway) have anything in them that would not/could not happen. This left me wondering if:
1. It is normal to have ID demanded from anyone at any time in America, by the police or even a train conductor (if so, what would that prove?)
2. Whether or not Americans are expected to carry some form of ID where ever they go (if this is the case America most certainly has become a police state, more than I thought it was).
Can someone answer this?