Ya, I got first hand experience with that situation, my poor mother had to smooth that situation over with her BOSS! (yes, she worked at the store I took candy from as a toddler)
How young are we talking here? That kid looks about five or so. If your kid hasn’t grasped the concept of “not yours” by the time they’re that old, there’s a problem.
Actually, a 5 year old wouldn’t fit in the trolley like that. This is more like 2-3 years old, and no, at that age, a child does not even grasp the concept of “Me”, much less “not mine”