I do not buy the argument that the zero rate is not OK but the low "error" airline fares are ok. Anyone knows that the super low airfares to Europe for $25.00 or even $135 are mistakes. If you have a problem with the zero Hilton rate but not with the $35.00 UA fare to CDG, then your logic fails me and your double standard smells of being a hypocrite. There is no way to convince me that United inteneded to have a fare for $35.00--period. The fact that one has money that changes hands and the other does not is irrelevant. Both companies made a mistake in their pricing and one honored it and the other is not.

Several years ago Alaska made a mistake with their companion fare being loaded into Sabre as a zero rate that could be booked by itself. Many travel agents grabed this zero rate only to have their clients turned away at check in unless they were willing to pay up to the lowest published fare at the time the original booking was made. The city pair involved was PDX to Palm Springs. United could have taken the same path Alaska did but decided not to. That says alot about United.

Please spare the legal talk, the core issue is customer service and how different companies respond to it.