This is an interesting one that I just saw on the wires:
NEW YORK (AP) -- United Airlines says it will start requiring minimum stays for nearly all domestic flights starting in October. It is also raising its cheapest fares by as much as $90 one-way.
...
Starting October 6, most United fares will require a one- to three-night or weekend-night minimum stay.
Apart from the obvious impact on mileage runners (do you guys feel special now or what?!) -- what about those of us who occasionally do day trips for business from SFO-LAX or the like? Ouch.
Perhaps I should wait to see the details....