How you know it's fugitive? Orange correctional clothing or stripes with a number sign perhaps? Could it be John McClane just having another bad day? A member of the Fight Club?
Most likely someone had a bit Amok run during the early hours or was found pants down on top of someone elses wife..
At least, cruising boats are too small for stowaways. They are a huge problem for commercialshipping. You can literally be stuck with the guy for years because immigration authorities are not all too keen to let him off the ship.