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Therefore, it was essential that the observed participants did not know anything about the observation because informing the participants about the study may have significantly changed their behaviour. Both the official IRB of the University of Hawai\u2019i, the \u2018Office of Research Compliance Human Studies Program of the University of Hawai\u2019i at Manoa\u2019, and the official \u2018Ethics Committee of the Faculty for Economy and Social Sciences at the University of T\u00fcbingen\u2019 informed us that, as the research had no direct or indirect interactions with the participants being observed, being that it was covert, the study is not regarded as a human subject research by definition of federal regulation of the USA and according to the German law. Therefore, the study does not need ethics approval nor informed consent [].","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare that they have no competing interests.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}},{"value":"Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Publisher\u2019s Note"}}],"article-number":"377"}}