Keep asking Bradon. Don't let the fact that some of these questions may seem elementary deter you from asking. There are no stupid questions....
Just stupid people
To defer simply means that team opts to make it's choice at the start of the second half. So they can choose to receive/kick or defend a goal to start the second half. The team that did not defer then gets the other option.
And yes, uninformed players sometimes make bad decisions when the other team defers.