Plugging in a request for "K" and higher fare classes was ignored for me today - all of the DL.com's trip options were returned with fare classes lower than K. I admit I haven't kept up with FT's now-colossal DL bug sticky thread - but it sure seems odd that DL's management apparently prefers to ignore their customer's attempts to send them more money that would result in the purchase of an economy-fare ticket that costs more than their lowest-priced ticket. No wonder DL's stock continues to tank.