When we went I stood at the turnstlis and put ALL the cards in and the rest of the family went thru.....I did not check to see if I was putting in a child's or adult's pass, or who went thru with which pass, and neither did the CM. There were 7 of us, and I think that the CM wasn't really paying attention to it. Maybe if someone was in a large group with a mix of kids and adults like we were then they could get away with it, but I think if were just 2 adults going thru, it would probably be noticed. I think that there is not THAT much savings in doing this anyway.....probably not worth the risk. Then again, the only thing that would probably happen is they would make you pay the difference and upgrade to an adult pass.....so you would not be out any more $ than if you had bought the adult pass in the 1st place. I seiously doubt that anyone doing this would be thrown in jail LOL!!! Probably not even kicked out of the parks, just made to upgrade!