I did an EX-ARN trip last year in March and was asked by the border agent (who ironically was the same ethnicity and religion as myself) why I was only staying for 1 night. I just showed him my flight itinerary and airport hotel reservation and was allowed through. However on the return back from my trip, I didn't get any questions what so ever upon presenting my passport and was given some good sightseeing tips for my one night stay.