There are probably people who know more than me, but I am pretty sure they know u have left the park once you leave. Not by “location services” as others have suggested but by RFID as you leave the park with your media - park ticket/magic band similarly how they know you were on a ride when your photo shows up in your photopass without ever tapping. I don’t think folks realize how much info is being tracked as you wear your magic bands. For example, I believe this is how they know when the parks reach capacity. In the old days, you would have to exit thru a turnstyle that counted the number of folks that have left.
Now, if my theory is true, you could I suppose tap in and then dispose of your magic band in the park. I have dozens of them so it wouldn’t be a big deal for me to lose one. Maybe that would work? But I bet u have issues when u tap back in.