chancer

That is just too simplistic. If you are getting a ticket for 1/200th of its actual value then it does matter how an airline conducts business. We aren't talking about hundreds of dollars of lost revenue per ticket like the majority of mistake fares but more like ten grand a pop. All that adds up quickly and something would need to make up the difference whether it be cuts in personnel, in-flight services, or maybe even safety. UA may seem like a big company, but it is not in any position to kiss millions and millions of dollars goodbye for the sake of goodwill.

As for the DOT's wrath, lawmakers are on United's side. This is quoted from the DOT: "The Enforcement Office has become concerned that increasingly mistaken fares are getting posted on frequent-flyer community blogs and travel-deal sites, and individuals are purchasing these tickets in bad faith and not on the mistaken belief that a good deal is now available."

Since new regs are still being debated, it's possible that your mistake fares could be reinstated, but keep this in mind: Any victory dance will be short-lived because, if UA is forced to honor these fares, it may well be the straw that finally breaks the camel's back. Next time there is another glitch, there may no longer be any DOT regs to protect those rock-bottom tickets.