I'm sorry but this is absolutely NOT true. It depends on the port authorities actually letting the ship stay late (and paying huge fees to do so). If the sea conditions and port space are not favorable, the ship will have to leave. However, if you are on a SHIP sponsored shore excursion, it is up to the cruise line to get you back to the ship at the next port of call, and they will pay for hotels, transportation, etc. But keep in mind there are times that the ship simply cannot wait for late excursions...it is beyond their control.