How things have changed. Maybe 30 years ago I got stuck in Gibraltar for a few days having returned by ferry from Morocco, because the airport was closed due to weather. No problem for most, as they just bus passengers to the bigger airport in Spain. But a problem for us, because we had run out of entries on our Schengen States visa. It also used to catch a lot of people out on the trains, with people not realizing their passports would be checked mid journey when crossing the borders.