Requiring one for boat rentals would kill the vessel rental businesses ...
Boater Ed Cards are required in Oregon, Washington and in BC ... I don't see any reason not to require it. More boater ed is not a bad thing. I'm sure it saves issues and probably even deaths. A card is not required in Alaska but it is much more common for the USCG, Troopers or NOAA to be on the boating grounds and boarding boaters for vessel and personal safety checks, as well as F&G violations.
I can see both sides of this issue. First I have been boating most of my life and I have actually read a fair amount about boating safety and rules so I don't think I need the card. However from what I see on the water boaters in general do not know much about safety or basic rules. Example you are responsible for any damage created by the wake created from your boat. Wake boarders do not care and think it is funny to create issues for guys in smaller vessels. They don't worry about creating wakes near boat docks that can damage boats tied to the dock.
Most lakes have a counter clockwise boating direction and you will see boaters going full speed on the wrong side all the time. Trolling and off plane is one thing full speed on the wrong side on a corner is a big problem. Maybe a boating safety course will get one boater to change their bad habits but I doubt it. After all everyone obeys all the traffic laws right?
Like BrnsvillyJohn, I've been boating all my life. I believe in education. So much so that my Dad and I signed up for both a USCG boating class as well as an independent sailing and navigation class; even though we don't sail, we wanted the knowledge that we get from it and most importantly, to be good navigators in the absence of electronic black boxes.
I could have passed the motorcycle road test on skill alone, but I chose to take the two day class in order to make me a better, safer rider. I got the same license in the end, but I also got the personal satisfaction to know I'm a safer rider because you can never be too safe on a motorcycle. Boats are no less dangerous.
Consider that I can go down to my local Camping World and buy a $250,000 Class A motor home, hook a 30' toyhauler trailer behind it with 8,000 pounds of side-by-sides in it and hit the road with no additional licensing requirements that I didn't get on my 16th birthday. Don't you think I should be required to show a knowledge of handling that kind of weight on the open road at 70 mph, right next to your 15 y/o daughter on the interstate? I've been towing for over 40 years, but anyone who thinks they can't learn anything new is a fool.
I get the additional tax argument, but safety is worth MUCH more than $10 per boater.