Warning messages have been used to disrupt individuals seeking online child sexual abuse material (CSAM) and promote engagement with support services, yet large-scale field evidence on message content remains limited, particularly in high anonymity environments. This study reports a field experiment on Ahmia.fi, a Tor search engine, examining how warning message content influences behavior. Across a 140-day period, almost 20 million searches were observed, with over 3 million searches containing known CSAM-related terms that triggered a warning linking to an anonymous self-help program. Users were exposed to warning messages varying in thematic content and framing, or a neutral message. Across a randomized comparison, a campaign-wide analysis, and interrupted time series models, message content consistently influenced engagement with help resources. All active messages increased click-through rates to help resources relative to the neutral condition, with a harm-focused message producing the strongest effects. At the platform level, click-through rates increased from 8.73% before the intervention to 15.67% during the campaign. These findings highlight the importance of message content in shaping responses to warning interventions, supporting an approach in which messaging is refined and adapted to increase engagement with support resources.

翻译：警告信息已被用于阻止个人获取网络儿童性虐待材料（CSAM）并鼓励其参与支持服务，然而关于信息内容的大规模实地证据仍然有限，特别是在高匿名性环境中。本研究在Tor搜索引擎Ahmia.fi上进行了一项实地实验，探究警告信息内容如何影响行为。在140天的观察期内，共监测到近2000万次搜索，其中超过300万次搜索包含已知的CSAM相关术语，触发了链接至匿名自助程序的警告。用户被曝露于不同主题内容和框架的警告信息，或中性信息。通过随机比较、活动范围分析以及中断时间序列模型，信息内容持续影响用户对帮助资源的参与度。与中性条件相比，所有主动信息均提高了帮助资源的点击率，其中以伤害为重点的信息效果最为显著。在平台层面，点击率从干预前的8.73%上升至活动期间的15.67%。这些发现凸显了信息内容在塑造对警告干预响应中的重要性，支持通过优化和调整信息内容以增加对支持资源参与度的方法。