The key to mco is being able to read the standby lists and when to go to the next option. A later flight could look wide open but if you don't see the oversold by 10plus on the first flight and the 30 NRSAs you will be shocked how fast things go south. Even 1 canceled flight early or the night before can cause issues. Not sure how many times I have gone to sleep and the first two flights to iah will have 20-30 open seats to then wake up and it's oversold by 20.

Plus on united they roll over the non united pilots on the jumpseat list (which I think is wrong). Someone can show up early knowing they won't make the flight and it will roll over to each flight before another jumpseater can even get to the gate to list when the gate agent shows up. Personally I feel it should be even/fair game for each flight for those UAX/OA where the list is flushed after each flight and those only with UA should be rolled over to the next flight.