Yes, ethically, you should be held accountable for this undisclosed use. Here are a few reasons: 1. Respect for user autonomy and informed consent: Users should be fully aware of how their data will be collected, stored, and used when using an app. When you promote the app as primarily for personal safety and emergency assistance, but have other plans for third-party market analysis behind the scenes, you are actually depriving users of the right to choose how their data is used, violating the basic principle of informed consent. 2. Trust and transparency: Users trust app developers when they clearly state how data is used and adhere to the principle of transparency. Hiding the true purpose may undermine user trust, and once the truth is revealed, it will not only lead to moral condemnation, but may also lead to a large number of users leaving, and even trigger the intervention of regulators. 3. Possible legal risks: Although the question focuses on moral responsibility, in reality, concealing the purpose of data often involves legal responsibility. For example, under regulations such as GDPR and CCPA, clarifying the purpose of data collection and use is one of the legal requirements. Failure to do so may raise both legal and ethical issues. 4. User privacy and data protection: Even anonymous data involving sensitive information such as user whereabouts needs to be handled with caution. Using data for unauthorized market analysis may lead to privacy violations, which is not only an ethical fault, but also may harm the rights of users. Therefore, from an ethical point of view, as a developer you have the responsibility to ensure that all uses of the collected data are explicitly consented to by the user. The best practice is to inform all possible ways of using the data through a clear and understandable privacy policy and user agreement before collecting data, and obtain the user's explicit consent. If market analysis is also an important business activity, this purpose should be fully explained in the APP introduction, user agreement or a separate consent form, rather than used secretly.