Graham ended up visiting about five houses this past Halloween. After the second one he was running up to front doors and sticking his hand into people's candy bowls, so we are pretty sure he "gets it".
At one point I looked in his little pumpkin and he had no candy. I couldn't figure out what had happened until I realized that his friend Ethan ("The Steeler"- literally and figuratively) had been emptying his candy every time we put them back in the wagon!
Here are a couple of pics of Graham on Halloween night and one of Mr. Sticky-Fingers Ethan in action!