The regulation acts on all people equally, the interpretation of the act by local officials does not.  From my personal experiences and those of colleagues with extensive International travel, I can assure you that regulations are used by local officials in anyway they wish. Including once in Singapore being kept in a room at the airport, with security outside, for 48 hrs with my Syrian PhD student because 'he looked like a terrorist'. We had planned a 48 hr stop over to do some sight seeing after a conference trip.

It happens. And it will happen