When I stayed at the Grand Californian for several days a couple of Octobers ago (cash booking since I was never able to grab anything w/ my
DVC points) I found early entry into MK to be an absolute cluster.
The security lines were ridiculous & there were literally hundreds/thousands of resort + off site guests queued for them, the entry turnstiles weren’t much better. You weren’t sorted until you were in the park, but to get to that sorting point there were really long lines, thus to enjoy that early half hour you’d probably have to start over an hour before just to make it through the crowds.
I expressed dissatisfaction with the way it was being handled in my survey. It’s unfortunate that DL took the cheap option & just eliminated early entry rather than dedicating a couple of security lines & entry turnstiles to the exclusive use of their resort guests during pre opening.