If you are planning a cruise holiday, make sure your passport has at least six months left on it, or you might not even be allowed to board. And check you have a visa for every stop you might make on the trip.
Many cruise operators will stop you boarding with alcohol. Don't throw anything overboard - especially a cigarette end.
And pranksters please note: Bomb hoaxes or 'man overboard' jokes are not welcome.
See what else will bring your cruise to an abrupt end in our video (above).