1. Goto map view
2. Place the map cursor over empty ground i.e. not over a vehicle
3. Select an AI squad member that's in a vehicle by pressing Fn key
4. Note that the command in the command menu in the top left of the screen has "move There" highlighted.
5. Deselect the AI squad member.
6. Move the map cursor so that it is over a vehicle on the map.
7. Press the Fn key to select the same AI squad member as before.
8. Observe that the command that is highlighted in the command menu will be "Move there" or "Disembark" depending on which vehicle you're hovered over when you select the player.