I think the cruise ships take the safety of their passengers pretty seriously, because their continued profitibility pretty much depends on them generally returning to port with the same number of passengers they left with. I'm therefore pretty sure there is system in place for crew members, even members of the lowly hotel staff, to report that a passenger has fallen overboard. (Even so, it's not unusual to hear reports of the ship not turning around for several hours.) I don't think, however, such a system exists for a bartender on the lido deck (I read the npr article, and it just says "a crew member," which leads me to believe it wasn't someone with much authority) to get the bridge's attention because they saw Moby Dick, a UFO, or someone waving a T shirt from a small boat a mile away. I doubt, for instance, anyone thought to pull a fire alarm, which are located all over the ship. That certainly would have gotten the bridge's attention, but it also may have resulted in punishment or dismissal for whomever missused the system.
But again, who knows.
