Jack Brown's is for fun, not for ratings!
That's because it is not much practical use anywhere else except Alaska to have a seaplane rating in the modern world.
They won't let you solo in Jack's seaplanes, if you earn a rating, which I did a few years back, go buy your own!
They take a lot of beating, those floats, on the water, you have to haul it out every day, pump it out (read Sir Francis Chichester's book and the troubles he had with water leaking into his floats!). If you think maintaining an aircraft in Europe is costing big moola, try maintaining anything that goes near salt water.......! and I bet they don't often let you land on lakes in the UK!
BUT, not withstanding, go for it. It is such a giggle. Doing that glassy water approach over the aligators basking on the shoreline. And in Florida, any lake NOT SPECIFICALLY PROHIBITED, is open for landing (watering).
However, whatever is on or in the water has the right of way over the airplane, boats, swimmers, manatees, etc etc etc. Because they have no way of knowing what your requirements are.
I was specially privileged one time to have a moonlight ride from a Louisiana Bayou on a Cessna 180 with floats - the pilot ran a business restocking offshore oil rigs. That was another story. Don't have to worry about weight and balance, just keep on roaring down the bayou until you have burnt enough fuel to get light enough for takeoff! Nine mile runway.