Even if it weren't a legal requirement I would hope people would have the common sense and desire for personal safety that they would have it there for a backup. I imagine our knowledge and surveillance of weather makes it a lot easier to sail if you have that information, but you could easily be stuck for a very long time if you only relied on sailing. From what I have read the Mayflower was delayed for over a month at sea due to the changing of the winds.

New phone, who dis?