(Blind) Users Really Do Heed Aural Telephone Scam Warnings

TL;DR

The paper addresses the accessibility gap in scam warnings by developing and evaluating aural contextual warnings for both legally blind and sighted users in naturalistic telephone scam settings. Using a deception-based, IRB-approved study with 72 participants across two scam scenarios and three warning conditions, the authors show that short and contextual aural cues effectively cue users to avoid scams, complementing STIR/SHAKEN indicators while also exposing privacy design considerations. Key findings include the rarity of pressing the scam button, the role of area codes and voice cues as decision aids, and strong support for context-rich warnings among blind users, albeit with privacy concerns and design trade-offs. The work suggests that usable, contextual aural warnings can meaningfully reduce scam susceptibility and provides pragmatic guidance for implementing accessible, privacy-conscious solutions in real-world devices and services.

Abstract

This paper reports on a study exploring how two groups of individuals, legally blind (n=36) and sighted ones (n=36), react to aural telephone scam warnings in naturalistic settings. As spoofing a CallerID is trivial, communicating the context of an incoming call instead offers a better possibility to warn a receiver about a potential scam. Usually, such warnings are visual in nature and fail to cater to users with visual disabilities. To address this exclusion, we developed an aural variant of telephone scam warnings and tested them in three conditions: baseline (no warning), short warning, and contextual warning that preceded the scam's content. We tested the two most common scam scenarios: fraud (interest rate reduction) and identity theft (social security number) by cold-calling participants and recording their action, and debriefing and obtaining consent afterward. Only two participants "pressed one" as the scam demanded, both from the legally blind group that heard the contextual warning for the social security scenario. Upon close inspection, we learned that one of them did so because of accessibility issues with their screen reader and the other did so intentionally because the warning convinced them to waste the scammer's time, so they don't scam vulnerable people. Both the legally blind and the sighted participants found the contextual warnings as powerful usable security cues that, together with STIR/SHAKEN indicators like "Scam Likely", would provide robust protection against any type of scam. We also discussed the potential privacy implications of the contextual warnings and collected recommendations for usably accessible implementation.

Figures (1)

• Figure 1: Contextual Telephone Scam Warning