Regulations Governing Immigration Inspection and Data Collection and Utilization Article 14

Upon immigration inspection, the NIA is entitled to examine a passenger’s boarding certificate or other certificate(s)/ document(s) related with entering the country.
中文原文 入出國查驗及資料蒐集利用辦法第14條
入出國查驗,於必要時,移民署得檢視乘客搭乘證明或與許可入國目的相符之證明文件。

English translation for reference only; the Chinese text prevails. Not legal advice.