@ Stanwell - well it's true that ideas get floated (ahem) without always coming to fruition. But consider that this is an "A-list" posh party island.
You're a London/Bucks/Hampshire music/TV celeb going to another 1%er's exclusive 11 am wedding on the island. The tides that day are low (causeway open) from 2 am to 6 am - so if you drive, you either get up at some ungodly hour, and then hang around in your wedding best for 5 more hours, having gotten your Roller or Rangerover all muddy on the causeway. (Google "Osea Island causeway" for images).
Or you catch a flight out of London City or somewhere else that delivers you to a nice dock (with a champers table laid on, no doubt) just in time for the event.
If you've got the brass - which would YOU pick?