Delta Airlines Bait & Switch on Upgrade , Internet

Delta Airlines tries to Bait & Switch you with their deceptive seat upgrade email ad soon after you book your flight. I confirmed my Seat this morning and at 3:00pm I received an email from Delta with the subject line: Your Flight Is Booked. Now Purchase An Economy Comfort Seat." The email ad states: "Enjoy more legroom and priority boarding for as low as $19." I logged into the Delta site, click on the email ad which says "Buy now." I see my flight, I select it, the screen briefly flashes "Loading seats" with "$19", then when you see the actual seating arrangement for your flight, the upgrade charge is $79, which or more than 4 times the low rate of $19 quoted in the ad (4 x $19 = $76). So the Delta Email Ad system is smart enough to know that you have confirmed a flight reservation but is clueless that your specific flight may have an upgrade fee that exceeds 4 times the teaser rate? I doubt it. This is a classic case of Bait & Switch! Bad business practice Delta!