I really dislike when this happens, it's a slap in the face to those of us who pay extra for main or C+ to see someone who paid for BE sitting in 1st. Especially when there are silver + medallions who are sitting in the back. I saw it happen yesterday some people on the upgrade list for C+ losing out to those with BE tickets because they went to the gate agent and flirted their way to a good seat before the upgrades auto kick in. I know it happened not only because I could see the seats getting taken and basic next to seats on the standby list, but because I was also sitting next to the gate agent because I was hoping for the 800 dollars they had offered to miss the flight. Unfortunately for me the flight took off without leaving anyone behind.