In Sept. we had an 8:10 ressie for CRT, MK did not require you to present your confirmation nor did they ask for your name. They allowed you into the turnstile with your park ticket...and then there was a line to the right next to the lockers and little Kodak Kiosk. Then at 8AM (park opening at 9am) they let the line in.
It was pretty easy to see.
You can only go so far...entrances to Fantasyland are blocked off.
At AK, they did ask for your name. But, there wasn't much organization so I could see how someone w/o ressies could slip in.