Adults should make sure to have the photo ID on hand just in case. If the scan doesn't recognize you (only about 5% of the time) and you don't have a photo ID, there's a whole process that has to be done. It's just faster to be prepared.
I can't tell you how many times I've seen people holding their 4-year-olds up to the scanner... meanwhile the AP is on the other side of the reader and the green arrow is on... Crazy.
Enjoy your AP!