What happened
Analysis and impact
从时间线看，Meta 在 WhatsApp 上的反诈骗动作是逐步推进的。今年早些时候，该公司先针对设备关联请求加入了诈骗检测——这类请求常被用于诱导用户把账号关联到攻击者设备上。现在推出的 Scam Alert 则把检测范围扩大到消息内容本身，通过设备端机器学习识别可疑信息。由于处理在本地完成，Meta 强调该功能在标记可疑内容时无需将消息上传至服务器，这与 WhatsApp 一贯强调的端到端加密定位保持一致。来源
该功能被描述为“可选”（optional），意味着用户需要主动开启才会生效。原文未提供具体的上线时间表、覆盖地区或更详细的技术实现说明。从产品逻辑看，设备端检测既是对隐私承诺的延续，也限制了云端模型可用的上下文信息，如何在本地条件下平衡误报与漏报，是这类功能常见的工程挑战。来源
References
Original source text
Meta is launching an optional Scam Alert feature on WhatsApp that uses on-device machine learning to flag suspicious messages. Earlier this year, Meta also launched scam detection for device linking requests on WhatsApp. The new Scam Alert feature, which is rolling out in a limited beta, shows users a warning if a chat seems like a scam:
If the model identifies a message as a likely scam attempt, the user sees a warning in the chat, which is not visible to the other person. From there, the user can decide what to do: block, report, or continue the conversation. If they decide that a warning is incorrectly flagged, the user can mark the cha …