Hi Georgia!
Welcome to the Disney Parks Moms Panel. My family has the exact same plan this coming fall and I had to do a little digging myself to figure this out, so I thought this was a great question!
Mickey's Not-So-Scary Halloween Party has traditionally started at 7 PM, and while it is subject to change, Guests with party tickets have been able to enter at 4 PM. When we go, we will be attending Mickey's Not-So-Scary Halloween Party on our first night and we will have 5 day park hopper after this, so I want to make sure that my hopper did not start a day early! I've heard from my fellow Moms Panelist that the system will automatically take your party ticket off if you enter after 4 PM, but things can be glitchy so I definitely don't think there is any harm in double checking!
When you enter the park, before you scan your
MagicBand for entry you should see a Cast Member walking around behind the entry point with an iPad. Tell the Cast Member at the scanning point that you'd like to make sure the correct park ticket is pulled and they will then flag the 'iPad Cast Member' over to you. They'll have you scan your Magic Band with them and they can tell which entry is being taken off. If it is incorrect they can fix it for you right there! I did it on my last trip because I had single day and hoppers loaded in my
My Disney Experience account and I wanted to make sure the single day ticket was used. It took less than a minute for them to check it for me!
Boo to you and I hope you have a Not-So-Scary time this fall during your trip to Walt Disney World! Please let us know if you have any other questions.
-Lindsey ºOº