No, an inspection at a port of entry is not a detention.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.
If you are referring to the brief passport/visa check when you go through customs at an airport, no, this is not what they're talking about. But if you have any questions about whether to answer yes or no to any question on your N-400 application, I recommend making an appointment with an attorney. It's very important that you answer the questions on your application correctly or you may inadvertently commit immigration fraud. Many attorneys offer free or low-cost consultations.
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