However, one thought stays with me and leaves me totally perplexed. That is, why is drinking alcohol permitted on boats on the Norfolk Broads?

We all know there are good and bad drinkers, there is no dispute there at all but when a boat collides with another vessel (note the use of the word, when, as opposed to, if) I would imagine it to be quite acceptable for a marine insurance company to refuse to pay out if the skipper was deemed as being intoxicated. Who could blame them either?
To me it just seems insane and furthermore I would have to assume that there would be a noticeable decrease in accidents on the Norfolk Broads.
Surely the idea of operating a vessel floating in water, weighing multiple tonnes and nearly fifty feet in length at times, could possibly be the root of a lot of negative issues on these charming waterways.
After all, if you were aware that many cars being driven passed you on the roads were being driven by folks drunk, would you even go out on the roads? In addition, you would expect there to be negative consequences as a result.
So I have to ask if these inland waterways are for boating, or just a place to go out and get p@@@@d?
Two packets of crisps, a crate of Stellar and a 45 footer please?....oh, can I have a 12 foot dinghy with that please?