It' a good idea if you can't swim and you are likely to be thrown overboard for some reason. What does it have to do with the size of the boat. People come up missing from cruise ships cause they went overboard, and just because it is during the winter months does not mean you will survive hypothermia if you are wearing your PFD, it only means you be floating dead instead of sunken dead in 5 minutes..(good for the family and friends). If you go out in frigid temps you probably should take the common sense measure to purchase and wear a cold emersion survival suit. It's like I said why do we wear a seat belt in any car at any time. If they are going to make a law at least have it make sense, if it for safety and survival. This is more about NY trying to settle the deficit on stupid laws to write tickets for than it is for our safety.
Any way, I'm glad I have a 22 foot boat instead of a 21 foot boat cause I'll be safe if I fall out without my PFD , especially in the winter months DUH