Yep and the sheer stupidity of it all is that the twist-lock plugs have been the origination point of hundreds of millions of dollars in losses. One twist-lock fire alone was in excess of 6 million....Sure it is. Burning boats are a liability to the marina and adjacent boats. And boat-side connections are a big culprit. Keep your boat in someone's marina and you are subject to a long list of their rules.
That doesn't mean they have to be smart rules.
I also find it quite amusuing that these marinas only care about what is on the outside of your boat... 55% of all boat fires are electrical and only a small chunk of that 55% are shore power related. 99.5% of boats don't even come close to meeting minimum accepted safety standards for electrical systems.....
Keep in mind that all standards organizations stop at the dock pedestal. Once on-board your boat they are merely suggested best safety standards, unless your insurer says otherwise...