I'll tell you what, when I was a little lad at the young age of 7, Pokémon cards where the hot shit during recess. Of course, none of us knew how to play the card game, but we collected them just because they looked cool. Anyway, one time this guy from the grade above mine comes up to me and says "that Crystal Kingdra is mine", then proceeded to take the card off of me and walk off. There was no way that card belonged to that prick, I never even interacted with him up until that point. Sever year-old me wasn't having that, so I caught up to him, yelled his name, and slapped him on the face before taking my card back. I got into some right trouble with the school staff, didn't help that everyone on the playground backed this guy up. But it was worth it, wasn't going to let some geezer take my Crystal Kingdra card. But I'll tell you what, if my nephew did that to me, I wouldn't slap or yell at him. That is because family is family, and I want to have a good and healthy relationship with him.