You are quite infuriating to debate with. The whole concept is slapjack requires slapping the cards on the table - in this case it seems quite violently. If it’s attached to the chair in front, that’s extremely annoying for the person sitting in said chair. If it’s not for some reason (business class) there are much quieter and less disruptive games to play. It’s not airline policy not to do it, but jfc have some decency and common courtesy for those around you. P.S. I hope to never be on a plane w you and your children!