The person experienced a tonic-clonic seizure not some sort of complex-partial seizure where they would flail about like a pinball. That type of seizure is extremely rare and is usually drug induced. A diabetic hyper-glycemic seizure could produce this effect.
I also believe you forget that people are on a cruise ship and not a naval vessel. The systems that anyone might possibly trigger would be a fire alarm. The ship systems such as life rafts or other systems that a passenger may be in contact with require more than a bump to set them off. If these systems were so delicate people stumbling in rough seas would be setting them off.
I do know where I come from. I've lived with epilepsy for ten years and work with neurologists and those who live with epilepsy. I lead a local epilepsy support group through the University of Minnesota and have worked with this for the last eight years.
I agree that a person with an active history of epilepsy should not be on a naval vessel or work with any dangerous equipment. However, a cruise ship is a completely different environment and your reasons do not "hold water".