I can understand how the Extra Magic Hours work in the morning, ie, you can't get in to the park early unless you can show that you are staying in a Disney resort or hotel.
However, I am not clear as to how the evening Extra Magic Hours work. If the park closing time is 10pm, are non-Disney residents sought out and escorted to the gate ?
Once you are in the park, how can they stop non-Disney residents from also enjoying the evening extra magic hours ?
Hopefully someone can explain this and it will become all too obvious.