I remember being in 3rd grade at St. John's Catholic school in Worcester Mass. in the late 60's and trying to trade cards at recess time. Or, if the nun's minding the school yard at recess saw anyone with cards in their hands worse yet playing flipping card games against the school building. They would come over and take everyone's cards away and never give them back. I guess they considered it gambling !
A strange thing was, that no one wanted anything to do with rookie cards. Kids would give them away or even throw them away !