The kid didn't approach Cullpepper like you described - In fact, from all accounts, it was a statement more "in jest" than a real request.
Cullpepper is the one who took advantage of the circumstances - not the kid.
Oh your right, The kid in the wheel chair and his tacky family had every right to believe that a tanger was just going to give them 75K worth of jewelry while surrouded by reporters from around the country.