I'm not an Attorney, however I think ownership starts after you leave the store, for anything you didn't bring with you upon entering.
That is the reason shoplifters are stopped "after" they walk out the door.
As long as someone is inside the store, it may be difficult to prove theft or intent of theft. However, once a customer leaves a store in possession of store merchandize he didn't pay for, the issue of intent becomes more provable.
"...I think ownership starts after you leave the store, for anything you didn't bring with you upon entering."
Does that mean I retain ownershop of whatever money I paid for that "anything" until I leave the store and my ownership of the "anything" starts?
Can I just go get it if I still retain ownership?
Or does the store have ownership of the money and the "anything" until I leave?
Is there any point at which I can have ownership of both the money and the "anything"?