In both of these cases, you must consider the potential of a person such as a family member, roommate, caregiver, etc. gaining unauthorized access to the chip card or the mobile device and performing transactions without the consumer's knowledge and then returning the card/mobile device back before the consumer recognizes that they have been taken.
Denying a claim solely on the basis of circumstantial evidence that does not directly tie the consumer to disputed transaction could open the institution up to regulatory criticism if we have a patten or practice of denying claims without hard evidence. Reg E is not a courtroom and does not require proof beyond a reasonable doubt to deny a claim, but institutions should avoid sweeping policies or procedures for denying claims based on these types of circumstances and investigate each claim based on its own merits.