i'm saying this because this is not a normal thing that people do. in fact its a very paranoid thing to do. you've given us very little background information on the situation so this is the best i can formulate from what you've provided
do you live in a sketchy neighborhood or something?
what color was the van? did it say free candy on the side?
was he wearing a hoodie or a polo collared shirt?
these are all valid questions