Reason for both to have a pass. We have used mine at lots of places, like you said, one pass, one carload. But, in some placesthat have a fee PER PERSON, they do require each person to have a pass. One place around here is the Nature Center at LBL. There is a fee per person, and each person with a pass does get a discount. Although, at one National Park that does charge per person, the rule was one pass, one family. So the same rules are not the same everywhere. Just spend the $10 one time and don't worry about it. Its still less than a average resturant meal, and its just one time.