Screen-photo classifiers must distinguish a device back from its display

A proof-of-possession classifier should not infer “displayed on a screen” merely because a physical document touches a phone or camera hardware is visible. The prompt and policy should require evidence that the proof subject is on the display side—such as lit pixels, moiré, backlighting, or a screen surface—and explicitly treat a physical card resting on a phone back/case as direct evidence. This applies to ID and document capture where users may use a phone or case as a surface. It does not weaken genuine screen-photo detection when display-level evidence is present.

Applies when: classifying whether a photographed document is physically present or displayed on another device. Keywords: proof of possession screen photo phone case physical document false positive