Would that hold up in court? If I sell you a car via a contract that says "if anybody steals the keys they now legally own the car" I suspect that would be diff

Would that hold up in court? If I sell you a car via a contract that says "if anybody steals the keys they now legally own the car" I suspect that would be difficult to enforce. And the thief would have to reveal themselves to assert their contractual right to own the car, thereby inviting criminal charges.