I don't own a boat yet, but one of my major concerns about owning one is getting hijacked or robbed or killed out at sea where I would be a long way from help. Is this something that rarely happens, or does everyone have to arm themselves?
There may be the outside chance that sailing the open ocean just isn't for you. Your fear of being attacked and murdered by armed thugs really is a bit over the top. There's a lot to worry about when cutting ties to a land based life. Your having "being hijacked, robbed or killed" as being a major concern is more than a little disturbing.
Skin cancer is a bigger threat to cruisers than criminals.