My girls are now grown and both are pregnant. But when we go with friends with kids they do the same thing. So the tradition lives on.

I said when the grand babies are born I want to be the one who grabs the apple.
I also use to go to garage sells and buy cheap costume jewelry. Or go get cheap rings and necklaces from the $1 store. When we went on Pirates and got to the treasure room with the skeletons my DH use to reach out with items hidden in his hand and place his hand in the water on the side of the boat and pull out the "pirate treasure". They each had a little box at home filled with the "stolen pirate treasure" from the ride...
We just got back from WDW with some friends with small children and did the apple and jewelry thing with the kids. There were 19 of us total and I bought a bunch of light up rings and cheap necklaces and gold pirate coins from the Oriental Trading Supply. I gave each adult a handful of stuff to hide and each child rode with one of them. At the same time we yelled, "Grab that treasure!" and reached in the water and came up with treasure. The kids all thought it was wonderful and wore the jewelry the rest of the trip. Only thing was that the kids wanted to go to the magic kingdom everyday so they could get more apples and treasure

I had bought enough stuff for several times on the ride but not twice a day for three weeks