Am I raising a thief?

So the other night Grandma(my mom)invited Cole to spend the night. Good huh? Well I go and pick him up and we stop at Blockbuster and Clint runs in to switch the movies. Well Cole pulls out a piece from one of my moms games, a pokemon one...He tells me "Mom, Grandma gave me all these." I say, "She gave them to you?" Long pause and Cole shakes his head. "Cole, did you steal those?" Long pause and he nods his head. So I call up my mom and tell her and then make Cole apologize. Cole gets on the phone and says sorry. My mom says "For what Cole?" "Stealing." "Are you going to bring them back?" Long pause followed by a quiet "Yes." Well today Cole is going to go do something for Grandma for stealing from her...I was having a hard time not laughing through the whole thing because Cole was so distraut...My mom told me that he had asked to play it and my mom told him to be careful to not lose any of the pieces. She came back a couple minutes later and it was put away all nicely, but some of the pieces were just put away nicely in Cole's backpack...