Guess alot of people who jumped at the cheap tkts on DH figuring they would fly someone else if need be and earn miles at a very cheap price , will be in for a rude awakening.
Guess the old saying still stands, You get what you pay for.
I think the NWA agents were DUMB for handling the OP or anyone else in such a way, very easy to have gained a potential new customer. But I dont blame them for not giving a seat assignment at Check-in , Standbys usually only get a seat at the Gate where they are Confirmed that in fact they are on the flight.