The only incident we could think of was when Once at a domestic airport, forgot water bottle in the luggage so it was pulled for extra checking. Them being new to US and not understanding the layout of the airport, they thought the checking was done when luggage was set in an area with no "keep out" thing or anything stopping entry, so they picked it up. The airport staff explained that they weren't done with the screening yet and made them go through the entire screening process and metal detectors again. Didn't ask for name,ID or anything else. Is that considered detained? Should they tick "yes" or "no" to thr question?