On the first day the scanner is used (day 7), there is an initial rule that states that any entrant from Kolechia must be searched in case they carry any weapons that can be used against any innocent Arstotzkans. Failure to do so results in a citation. The rule is later repealed due to the Kolechian government filing a complaint but the search option remains in use for the rest of the game.
Even if a search is available to clear a discrepancy, the player is not required to perform the search and can instead, without a citation, deny the entrant outright based on the discrepancy that enabled the search option. Unless the reason for denial stamp is in play (since day 18), it is not even necessary to interrogate about the discrepancy. Thus all Kolechians can be denied on day 7 without searching them or being cited for violations; the rule is implemented so that having a Kolechian passport is a "discrepancy". This might not be intentional on the part of the developer. Note that once the search is performed, the discrepancy may be cleared, in which case the entrant cannot be denied entry based on the cleared discrepancy. The player must look for another discrepancy, and if there is none, approve entry.
The images from the search scanner will show nudity in the form of genitals for males and breasts for females if the option is turned on. Otherwise it just shows their underwear/undershirts.