Account sharing is common in subscription services and is now extending to generative AI platforms, which are still primarily designed for individual use. Sharing often requires workarounds that create new tensions. This study examines how LLM subscriptions are shared and the norms that develop. We combined a survey of 245 users with interviews of 36 participants to understand both patterns and lived experiences. Our analysis identified four types of account sharing, organized along two dimensions: whether the owner uses the account and whether subscription costs are shared. Within these types, we examined how norms were formed and how their fragility, especially privacy, became evident in practice. Users, fully aware of this, subtly adjusted their behavior, which we interpret through the lens of the observer effect. We frame LLM account sharing as a social practice of appropriation and outline design implications to adapt single-user platforms to multi-user realities.

翻译：账户共享在订阅服务中普遍存在，并正向主要针对个体用户设计的生成式AI平台扩展。共享通常需要变通方法，这引发了新的矛盾。本研究探讨了LLM订阅如何被共享，以及在此过程中形成的规范。我们结合了对245名用户的问卷调查与对36名参与者的深度访谈，以理解共享模式与用户真实体验。分析识别出四种账户共享类型，依据两个维度划分：所有者是否使用账户、订阅费用是否分摊。在这些类型中，我们考察了规范如何形成，以及其脆弱性（尤其是隐私问题）如何在实践中显现。用户对此心知肚明，并微妙地调整自身行为——我们通过观察者效应视角对此进行解读。我们将LLM账户共享定位为一种社会性的挪用实践，并针对如何将单用户平台适配至多用户现实情境，提出了设计启示。