The newspaper analogy isn't really applicable. First, a newspaper ad does not involve any action by the user. Here, on the other hand, the customer has affirmatively clicked a button that is supposed to return first class flight options, yet has received segments in economy. Second, a newspaper ad will put an asterisk or other indicator next to the text that has restrictions. Thus, the reader is made aware of said rules or restrictions. Here, there is no asterisk or any other warning next to where the user clicks the search for first class flights.

Let's take it one step further: United.com's "search by schedule" screen displays a price. As we know, that price is sometimes wrong. When the price is wrong, and the user goes to the confirmation screen, United.com displays a message, in red text, saying that "a price change has occurred," or something to that effect. Thus, the price change is made obvious to the user. The same ought to be done for a cabin change.

Lastly, this should not be an issue of caveat emptor, as you said in an earlier post. If it were, that would imply United were trying to pull a fast one on its customers.

Just because we FTers know what to look for on United's website doesn't mean the general public does.