What's interesting to me, though, is that they seem to only be doing this on the ATL route (based on other comments in this thread). In the past few months, I have flown each of DTW-LAS, MEM-LAS and MSP-LAS (DTW and MSP on multiple occasions). All flights on Friday nights, leaving the hubs at roughly the same time (last flight out, 9-10pm). Each of my flights have cleared at the window. So, why do this on ATL but not the other routes? I'm sure the easy answer is FCM, so maybe a dumb question but I would think it has more to do with thinking they could sell upgrades to LAS regardless of origin of the flight.